JP7655321B2 - Base station device, terminal device, and communication method - Google Patents

Description

The present disclosure relates to a base station device, a terminal device, and a communication method.

Radio access methods and radio networks for cellular mobile communications (hereinafter referred to as "Long Term Evolution (LTE)", "LTE-Advanced (LTE-A)", "LTE-Advanced Pro (LTE-A Pro)", "New Radio (NR)", "New Radio Access Technology (NRAT)", "Evolved Universal Terrestrial Radio Access (EUTRA)", or "Further EUTRA (FEUTRA)") are being considered by the 3rd Generation Partnership Project (3GPP). In the following description, LTE includes LTE-A, LTE-A Pro, and EUTRA, and NR includes NRAT and FEUTRA. In LTE, the base station device (base station, communication device) is called eNodeB (evolved NodeB), in NR, the base station device (base station, communication device) is called gNodeB, and in LTE and NR, the terminal device (mobile station, mobile station device, terminal, communication device) is called UE (User Equipment). LTE and NR are cellular communication systems in which the areas covered by the base station device are arranged in multiple cells. A single base station device may manage multiple cells.

NR has the characteristics of ultra-high speed, low latency, high reliability, and multiple simultaneous connections. As one of the use cases of NR that makes use of these characteristics, its use in services using Augmented Reality (AR) and Virtual Reality (VR) is being considered. For example, with AR technology, it is possible to superimpose various forms of virtual content such as text, icons, or animations on real objects captured in images of the real space and present them to the user. Non-Patent Documents 1 and 2 disclose use cases and (potential) requirements for services using Augmented Reality (AR) and Virtual Reality (VR) (e.g., AR/VR games).

3GPP TR 22.842, V17.1.0 (2019-09) 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Study on Network Controlled Interactive Services (Release 17) 3GPP TS 22.261 v17.0.1 (2019-10) 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Service requirements for next generation new services and markets (Release 17)

NR is expected to be used to transmit 4K and 8K video due to its characteristics of ultra-high speed, low latency, high reliability, and multiple simultaneous connections. In addition, wearable devices are expected to become more widespread as a post-smartphone. Some use cases for wearable devices require consideration of not only ultra-high speed, but also low latency and high reliability. For example, in cases where VR content is displayed wirelessly on an HMD (Head Mounted Display), it is important to keep the motion-to-photon latency within a certain value to prevent VR sickness. In this way, it is necessary to deliver video content that requires real-time performance so that it can be displayed stably.

Therefore, this disclosure proposes technology that contributes to the realization of stable video content distribution that can be displayed.

Note that the above problem or objective is merely one of several problems or objectives that can be solved or achieved by the multiple embodiments disclosed in this specification.

According to the present disclosure, a base station device is provided. The base station device includes a wireless communication unit and a control unit. The wireless communication unit transmits video data to a terminal device at a predetermined period. The control unit changes a setting related to the reception timing when a difference between a periodic reception timing at which the terminal device receives the video data and a display timing of the video data displayed on the terminal device at a predetermined frame rate satisfies a predetermined condition.

FIG. 1 is a diagram illustrating a configuration example of a content delivery system according to an embodiment of the present disclosure. FIG. 1 is a diagram illustrating a configuration example of an information processing device according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating a configuration example of a base station device according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating a configuration example of a terminal device according to an embodiment of the present disclosure. A diagram showing an example of 5G architecture. FIG. 11 is a sequence diagram illustrating an example of a content delivery process according to an embodiment of the present disclosure. FIG. 11 is a diagram for explaining an example of a rendering process according to an embodiment of the present disclosure. FIG. 11 is a diagram for explaining another example of the rendering process according to an embodiment of the present disclosure. FIG. 11 is a sequence diagram illustrating an example of a registration process according to an embodiment of the present disclosure. A sequence diagram showing an example of a PDU session establishment process according to an embodiment of the present disclosure. 1 is a sequence diagram illustrating an example of an RRC_CONNECTED transition process according to an embodiment of the present disclosure. FIG. 1 is a diagram for explaining an example of video data distribution by a content distribution system. A figure for explaining SPS reconfiguration by a base station device according to an embodiment of the present disclosure. 1 is a flowchart illustrating a flow of an SPS reconfiguration process according to an embodiment of the present disclosure. A figure for explaining an example of SPS setting by a base station device according to an embodiment of the present disclosure. A figure for explaining an example of SPS setting by a base station device according to an embodiment of the present disclosure. A figure for explaining an example of SPS setting by a base station device according to an embodiment of the present disclosure. 11 is a diagram for explaining CG reconfiguration by a base station device according to an embodiment of the present disclosure. FIG. 11 is a diagram for explaining CG reconfiguration by a base station device according to an embodiment of the present disclosure. FIG. 11 is a diagram for explaining an example of a display process by a terminal device according to an embodiment of the present disclosure. FIG. 11A and 11B are diagrams for explaining another example of the display process by the terminal device according to an embodiment of the present 11 is a diagram for explaining an example of a video data allocation process by a base station device according to an embodiment of the present disclosure. FIG. 11 is a diagram for explaining an example of a video data allocation process by a base station device according to an embodiment of the present disclosure. FIG. 11 is a diagram for explaining an example of a video data allocation process by a base station device according to an embodiment of the present disclosure. FIG. 11 is a diagram for explaining an example of a video data allocation process by a base station device according to an embodiment of the present disclosure. FIG. This is an illustration of the rendering server and AR/VR client involved in rendering.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

In addition, in this specification and drawings, similar components of the embodiments may be distinguished by adding different alphabets after the same reference numerals. However, if there is no need to particularly distinguish between each of the similar components, only the same reference numerals will be used.

One or more of the embodiments (including examples and variations) described below can be implemented independently. However, at least a portion of the embodiments described below may be implemented in appropriate combination with at least a portion of other embodiments. These multiple embodiments may include novel features that are different from one another. Thus, these multiple embodiments may contribute to solving different purposes or problems and may provide different effects from one another.

The explanation will be given in the following order.
1. Configuration example of content distribution system 1.1. Overall configuration example of content distribution system 1.2. Configuration example of information processing device 1.3. Configuration example of base station device 1.4. Configuration example of terminal device 1.5. Configuration example of network architecture 2. Information processing example of content distribution system 2.1. Content distribution processing example 2.2. Rendering processing example 2.3. Communication processing example 3. Technical issues 4. Technical features 4.1. SPS reconfiguration 4.2. Multiple SPS configuration 4.3. CG reconfiguration 4.4. Time warp change 4.5. Priority setting 5. Other embodiments 6. Application example 7. Conclusion

<<1. Example of the configuration of a content distribution system>>
<1.1. Example of overall configuration of content distribution system>
1 is a diagram showing a configuration example of a content distribution system 100 according to an embodiment of the present disclosure. The content distribution system 100 is a system that distributes video content to a terminal device 110 via a wireless access network. Here, the wireless access network may be an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) or a Next Generation Radio Access Network (NG-RAN).

The content distribution system 100 includes a terminal device 110, a base station device 130, and an information processing device 150. In the content distribution system 100, video content is distributed from the information processing device 150 to the terminal device 110 via the base station device 130.

The terminal device 110 and the base station device 130 are connected via the above-mentioned wireless access network. The base station device 130 and the information processing device 150 may be connected via a wireless or wired access network.

The devices in the diagram may be considered devices in a logical sense. In other words, some of the devices in the diagram may be realized as virtual machines (VMs), containers, Dockers, etc., and these may be implemented on the same physical hardware.

Note that an LTE base station may be referred to as an eNodeB (Evolved Node B) or eNB. Also, an NR base station may be referred to as an NGRAN Node (Next Generation RAN node), gNodeB or gNB. Also, in LTE and NR, a terminal device (also referred to as a mobile station, mobile station device, or terminal) may be referred to as a UE (User Equipment). Note that a terminal device is a type of communication device, and may also be referred to as a mobile station, mobile station device, or terminal.

In this embodiment, the concept of a communication device includes not only portable mobile devices (terminal devices) such as mobile terminals, but also devices installed in structures or mobile bodies. The structures and mobile bodies themselves may be considered as communication devices. Furthermore, the concept of a communication device includes not only terminal devices, but also base station devices. A communication device is a type of processing device and information processing device. A communication device can also be referred to as a transmitting device or a receiving device.

[Information processing device]
The information processing device 150 is a content management device that manages video content in the terminal device 110. The information processing device 150 is, for example, a personal computer, a workstation, or a game device. The information processing device 150 may also be a device collectively referred to as a cloud server or an edge server.

[Base station equipment]
The base station device 130 is a wireless communication device that wirelessly communicates with the terminal device 110. The base station device 130 is a type of communication device. The base station device 130 is also a type of information processing device.

The base station device 130 may be composed of a collection of multiple physical or logical devices. For example, in the embodiment of the present disclosure, the base station device 130 may be divided into multiple devices, a BBU (Baseband Unit) and a RU (Radio Unit), and may be interpreted as a collection of these multiple devices. Additionally or alternatively, in the embodiment of the present disclosure, the base station device 130 may be either or both of a BBU and a RU. The BBU and the RU may be connected by a predetermined interface (e.g., eCPRI). Additionally or alternatively, the RU may be referred to as a Remote Radio Unit (RRU) or a Radio DoT (RD). Additionally or alternatively, the RU may be compatible with a gNB-DU, which will be described later. Additionally or alternatively, the BBU may be compatible with a gNB-CU, which will be described later. Additionally or alternatively, the RU may be a device formed integrally with an antenna. The antenna of the base station device 130 (for example, an antenna integrally formed with the RU) may adopt an Advanced Antenna System and support MIMO (for example, FD-MIMO) and beamforming. In the Advanced Antenna System, the antenna of the base station device 130 (for example, an antenna integrally formed with the RU) may have, for example, 64 transmitting antenna ports and 64 receiving antenna ports. The antenna mounted on the RU may be an antenna panel composed of one or more antenna elements, and the RU may be equipped with one or more antenna panels. For example, the RU may be equipped with two types of antenna panels, a horizontally polarized antenna panel and a vertically polarized antenna panel, or a right-handed circularly polarized antenna panel and a left-handed circularly polarized antenna panel. The RU may form and control an independent beam for each antenna panel.

In addition, multiple base station devices 130 may be connected to each other. One or more base station devices 130 may be included in a radio access network (RAN). That is, the base station device 130 may simply be referred to as a RAN, a RAN node, an AN (Access Network), or an AN node. The RAN in LTE is called EUTRAN (Enhanced Universal Terrestrial RAN). The RAN in NR is called NGRAN. The RAN in W-CDMA (UMTS) is called UTRAN. The base station device 130 in LTE is called eNodeB (Evolved Node B) or eNB. That is, the EUTRAN includes one or more eNodeBs (eNBs). In addition, the base station device 130 in NR is called gNodeB or gNB. That is, the NGRAN includes one or more gNBs. Furthermore, the EUTRAN may include a gNB (en-gNB) connected to a core network (EPC) in an LTE communication system (EPS). Similarly, the NGRAN may include an ng-eNB connected to a core network 5GC in a 5G communication system (5GS). Additionally or alternatively, when the base station device 130 is an eNB, gNB, or the like, it may be referred to as 3GPP Access. Additionally or alternatively, when the base station device 130 is a wireless access point (Access Point), it may be referred to as Non-3GPP Access. Additionally or alternatively, the base station device 130 may be a radio extension device called an RRH (Remote Radio Head). Additionally or alternatively, when the base station device 130 is a gNB, the base station device 130 may be referred to as a combination of the above-mentioned gNB CU (Central Unit) and gNB DU (Distributed Unit) or any of them. The gNB CU (Central Unit) hosts multiple upper layers (e.g., RRC, SDAP, PDCP) of the Access Stratum for communication with the UE. On the other hand, the gNB-DU hosts multiple lower layers (e.g., RLC, MAC, PHY) of the Access Stratum. That is, among the messages and information described later, RRC signaling (e.g., various SIBs including MIB and SIB1, RRCSetup message, RRCReconfiguration message) may be generated by the gNB CU, while DCI and various Physical Channels (e.g., PDCCH, PBCH) described later may be generated by the gNB-DU. Alternatively, among the RRC signaling, some configurations such as IE:cellGroupConfig may be generated by the gNB-DU, and the remaining configurations may be generated by the gNB-CU. These configurations may be transmitted and received via the F1 interface described later. The base station device 130 may be configured to be able to communicate with other base station devices 130. For example, when multiple base station devices 130 are eNBs or a combination of an eNB and an en-gNB, the base station devices 130 may be connected to each other via an X2 interface. Additionally or alternatively, when multiple base station devices 130 are gNBs or a combination of a gn-eNB and a gNB, the devices may be connected to each other via an Xn interface. Additionally or alternatively, when multiple base station devices 130 are a combination of a gNB CU (Central Unit) and a gNB DU (Distributed Unit), the devices may be connected to each other via the above-mentioned F1 interface. Messages and information (information included in RRC signaling or DCI) described later may be communicated between multiple base station devices 130 (e.g., via the X2, Xn, and F1 interfaces).

Furthermore, as described above, the base station device 130 may be configured to manage multiple cells. The cell provided by the base station device 130 is called a serving cell. The serving cell includes a PCell (Primary Cell) and a SCell (Secondary Cell). When dual connectivity (e.g., EUTRA-EUTRA Dual Connectivity, EUTRA-NR Dual Connectivity (ENDC), EUTRA-NR Dual Connectivity with 5GC, NR-EUTRA Dual Connectivity (NEDC), NR-NR Dual Connectivity) is provided to a UE (e.g., terminal device 110), the PCell and zero or more SCell(s) provided by the MN (Master Node) are called a Master Cell Group. Furthermore, the serving cell may include a PSCell (Primary Secondary Cell or Primary SCG Cell). That is, when dual connectivity is provided to a UE, the PSCell and zero or more SCell(s) provided by the SN (Secondary Node) are called a Secondary Cell Group (SCG). Unless a special configuration (e.g., PUCCH on SCell) is made, the physical uplink control channel (PUCCH) is transmitted on the PCell and PSCell, but not on the SCell. Radio Link Failure is also detected on the PCell and PSCell, but not on the SCell (does not need to be detected). As described above, the PCell and PSCell are also called Special Cells (SpCells) because they have a special role in the Serving Cell(s). One cell may be associated with one Downlink Component Carrier and one Uplink Component Carrier. Also, the system bandwidth corresponding to one cell may be divided into multiple Bandwidth Parts. In this case, one or multiple Bandwidth Parts (BWPs) may be configured in the UE, and one Bandwidth Part may be used by the UE as an Active BWP. Furthermore, the radio resources (e.g., frequency band, numerology (subcarrier spacing), slot format (Slot configuration)) that the terminal device 110 can use may differ for each cell, each component carrier, or each BWP.

[Terminal Device]
The terminal device 110 is a wireless communication device that wirelessly communicates with the base station device 130. The terminal device 110 is, for example, a mobile phone, a smart device (a smartphone or a tablet), a PDA (Personal Digital Assistant), or a personal computer. The terminal device 110 may be a head mounted display or VR goggles that have a function of wirelessly transmitting and receiving data.

The terminal device 110 may also be capable of sidelink communication with other terminal devices 110. When performing sidelink communication, the terminal device 110 may be able to use an automatic retransmission technique such as HARQ (Hybrid Automatic Repeat reQuest). The terminal device 110 may be capable of NOMA (Non Orthogonal Multiple Access) communication with the base station device 130. The terminal device 110 may also be capable of NOMA communication in communication (sidelink) with other terminal devices 110. The terminal device 110 may also be capable of LPWA (Low Power Wide Area) communication with other communication devices (e.g., the base station device 130 and other terminal devices 110). In addition, the wireless communication used by the terminal device 110 may be wireless communication using millimeter waves. The wireless communication used by the terminal device 110 (including sidelink communication) may be wireless communication using radio waves, or wireless communication using infrared rays or visible light (optical wireless).

The terminal device 110 may simultaneously connect to multiple base station devices or multiple cells to perform communication. For example, when one base station device can provide multiple cells, the terminal device 110 can perform carrier aggregation by using one cell as a pCell and another cell as an sCell. Also, when multiple base station devices 130 can each provide one or multiple cells, the terminal device 110 can realize DC (Dual Connectivity) by using one or more cells managed by one base station device (MN (e.g., MeNB or MgNB)) as a pCell, or a pCell and an sCell(s), and using one or more cells managed by the other base station device (SN (e.g., SeNB or SgNB)) as a pCell (PSCell), or a pCell (PSCell) and an sCell(s). DC may be referred to as MC (Multi Connectivity).

In addition, when a communication area is supported through cells of different base station devices 130 (multiple cells with different cell identifiers or the same cell identifier), it is possible to bundle the multiple cells and communicate between the base station device 130 and the terminal device 110 using carrier aggregation (CA) technology, dual connectivity (DC) technology, or multi-connectivity (MC) technology. Alternatively, it is also possible for the terminal device 110 to communicate with the multiple base station devices 130 via the cells of the different base station devices 130 using coordinated multi-point transmission and reception (CoMP) technology.

The configuration of each device that constitutes the content distribution system 100 is described in detail below. Note that the configuration of each device shown below is merely an example. The configuration of each device may differ from the configuration shown below.

<1.2. Example of configuration of information processing device>
FIG. 2 is a diagram showing a configuration example of an information processing device 150 according to an embodiment of the present disclosure. The information processing device 150 is, for example, a device that manages or generates video content. The information processing device 150 includes a communication unit 151, a storage unit 152, and a control unit 153. Note that the configuration shown in FIG. 2 is a functional configuration, and the hardware configuration may be different from this. In addition, the functions of the information processing device 150 may be distributed and implemented in multiple physically separated configurations. For example, the information processing device 150 may be configured by multiple server devices.

The communication unit 151 is a communication interface for communicating with other devices. The communication unit 151 may be a network interface or a device connection interface. For example, the communication unit 151 may be a LAN (Local Area Network) interface such as a NIC (Network Interface Card), or a Universal Serial Bus (USB) interface configured with a USB host controller, a USB port, etc. The communication unit 151 may be a wired interface or a wireless interface. The communication unit 151 functions as a communication means of the information processing device 150. The communication unit 151 communicates with the base station device 130 according to the control of the control unit 153.

The storage unit 152 is a storage device capable of reading and writing data, such as a dynamic random access memory (DRAM), a static random access memory (SRAM), a flash memory, or a hard disk. The storage unit 152 functions as a storage means of the information processing device 150. The storage unit 152 stores, for example, video content.

The control unit 153 is a controller that controls each part of the information processing device 150. The control unit 153 is realized by a processor such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or a GPU (Graphics Processing Unit). For example, the control unit 153 is realized by the processor executing various programs stored in a storage device inside the information processing device 150 using a RAM (Random Access Memory) or the like as a working area. The control unit 153 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The CPU, MPU, GPU, ASIC, and FPGA can all be considered as controllers.

The control unit 153 includes an inertial measurement information acquisition unit 1531, a video data generation unit 1532, and a wireless resource allocation request unit 1533. Each block constituting the control unit 153 (the inertial measurement information acquisition unit 1531 to the wireless resource allocation request unit 1533) is a functional block indicating the function of the control unit 153. These functional blocks may be software blocks or hardware blocks. For example, each of the above-mentioned functional blocks may be a software module realized by software (including a microprogram), or may be a circuit block on a semiconductor chip (die). Of course, each functional block may be a processor or an integrated circuit. The method of configuring the functional blocks is arbitrary. The control unit 153 may be configured in functional units different from the above-mentioned functional blocks.

The inertial measurement information acquisition unit 1531 acquires inertial measurement information from the terminal device 110 via the base station device 130. The inertial measurement information is information related to inertia, such as acceleration information and angular velocity information of the terminal device 110, and detection results (e.g., the direction of the user's gaze) detected by a sensor mounted on the terminal device 110. The inertial measurement information is, for example, information indicating the state of the user using the terminal device 110 (e.g., the direction of the head and gaze, etc.). As a more specific example, the information related to inertia may be the amount of change in each of the components in the yaw direction, pitch direction, and roll direction as the movement of the user's head. These components may be detected by a sensor mounted on the terminal device 110 (an acceleration sensor or an angular velocity sensor (gyro sensor)).

The video data generation unit 1532 determines the area of the video based on the acquired inertial measurement information, and generates video data to be distributed to the terminal device 110. The video data generation unit 1532 determines the video area to distribute the video in the direction the user is looking based on the inertial measurement information, and generates the video data.

The wireless resource allocation request unit 1533 requests the base station device 130 to allocate wireless resources to be used for transmitting video data.

The control unit 153 may acquire information related to an operation input by the user from the terminal device 110 via the base station device 130, determine an area of the video based on the information related to the operation, and generate video data to be distributed to the terminal device 110. Here, the operation input by the user may be, for example, an operation in a game, an operation for remotely controlling or driving a device, etc.

<1.3. Example of base station device configuration>
Next, a description will be given of the configuration of the base station device 130. Fig. 3 is a diagram illustrating an example of the configuration of the base station device 130 according to an embodiment of the present disclosure.

The base station device 130 includes a communication unit 131, a storage unit 132, a network communication unit 133, and a control unit 134. Note that the configuration shown in FIG. 3 is a functional configuration, and the hardware configuration may be different from this. In addition, the functions of the base station device 130 may be distributed and implemented in multiple physically separated configurations.

The communication unit 131 is a signal processing unit for wireless communication with other wireless communication devices (e.g., terminal device 110 and other base station devices 130). The communication unit 131 operates under the control of the control unit 134. When the other wireless communication device is a terminal device 110, the communication unit 131 may be a wireless transceiver compatible with one or more wireless access methods. For example, the communication unit 131 supports both NR and LTE. The communication unit 131 may support W-CDMA and cdma2000 in addition to NR and LTE. The communication unit 131 may also support communication using NOMA. When the other wireless communication device is another base station device 130, the communication unit 131 may be an X2 interface, an Xn interface, or an F1 interface.

The communication unit 131 includes a reception processing unit 1311, a transmission processing unit 1312, and an antenna 1314. The communication unit 131 may include a plurality of reception processing units 1311, transmission processing units 1312, and antennas 1314. When the communication unit 131 supports a plurality of wireless access methods, each unit of the communication unit 131 may be configured individually for each wireless access method. For example, the reception processing unit 1311 and the transmission processing unit 1312 may be configured individually for LTE and NR.

The reception processing unit 1311 processes the uplink signal received via the antenna 1314. The reception processing unit 1311 operates as a receiving unit that receives the received signal. The reception processing unit 1311 includes a radio receiving unit 1311a, a multiplexing/demultiplexing unit 1311b, a demodulation unit 1311c, and a decoding unit 1311d.

The wireless receiver 1311a performs down-conversion, removal of unnecessary frequency components, control of amplification level, orthogonal demodulation, conversion to digital signal, removal of guard interval (cyclic prefix), extraction of frequency domain signal by fast Fourier transform, etc. on the uplink signal. The demultiplexer 1311b separates uplink channels such as PUSCH (Physical Uplink Shared Channel) and PUCCH (Physical Uplink Control Channel) and uplink reference signals from the signal output from the wireless receiver 1311a.

The demodulator 1311c demodulates the received signal using a modulation method such as BPSK (Binary Phase Shift Keying) or QPSK (Quadrature Phase Shift Keying) for the modulation symbols of the uplink channel. The modulation method used by the demodulator 1311c may be 16QAM (Quadrature Amplitude Modulation), 64QAM, or 256QAM. In this case, the signal points on the constellation do not necessarily have to be equidistant. The constellation may be a non-uniform constellation (NUC).

The decoder 1311d performs a decoding process on the coded bits of the demodulated uplink channel. The decoded uplink data and uplink control information are output to the controller 134.

The transmission processing unit 1312 performs transmission processing of downlink control information and downlink data. In this manner, the transmission processing unit 1312 is an acquisition unit that acquires bit sequences such as downlink control information and downlink data from the control unit 134. The transmission processing unit 1312 includes an encoding unit 1312a, a modulation unit 1312b, a multiplexing unit 1312c, and a radio transmission unit 1312d.

The encoding unit 1312a encodes the downlink control information and downlink data input from the control unit 134 using an encoding method such as block encoding, convolutional encoding, turbo encoding, etc. The encoding unit 1312a may also encode the downlink control information and downlink data using a polar code or a low density parity check code (LDPC code).

The modulation unit 1312b modulates the coded bits output from the coding unit 1312a using a predetermined modulation method such as BPSK, QPSK, 16QAM, 64QAM, or 256QAM. In this case, the signal points on the constellation do not necessarily have to be equidistant. The constellation may be a non-uniform constellation.

The multiplexing unit 1312c multiplexes the modulation symbols of each channel and the downlink reference signal, and places them in a predetermined resource element. The wireless transmission unit 1312d performs various signal processing on the signal from the multiplexing unit 1312c. For example, the wireless transmission unit 1312d performs processing such as conversion from the time domain to the frequency domain by fast Fourier transform, addition of a guard interval (cyclic prefix), generation of a baseband digital signal, conversion to an analog signal, quadrature modulation, up-conversion, removal of unnecessary frequency components, and power amplification. The signal generated by the transmission processing unit 1312 is transmitted from the antenna 1314.

The memory unit 132 is a storage device capable of reading and writing data, such as a DRAM, an SRAM, a flash memory, or a hard disk. The memory unit 132 functions as a storage means of the base station device 130.

The network communication unit 133 is a communication interface for communicating with a node (e.g., the information processing device 150) located at a higher position on the network. For example, the network communication unit 133 may be a LAN interface such as a NIC. Additionally or alternatively, the network communication unit 133 may be an S1 interface or an NG interface for connecting to a core network node. The network communication unit 133 may be a wired interface or a wireless interface. The network communication unit 133 functions as a network communication means of the base station device 130.

The control unit 134 is a controller that controls each part of the base station device 130. The control unit 134 is realized by a processor (hardware processor) such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). For example, the control unit 134 is realized by the processor executing various programs stored in a storage device inside the base station device 130 using a RAM (Random Access Memory) or the like as a working area. The control unit 134 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The CPU, MPU, ASIC, and FPGA can all be considered as controllers.

The control unit 134 includes a radio resource allocation setting unit 1341. The blocks constituting the control unit 134 (radio resource allocation setting unit 1341) are functional blocks indicating the functions of the control unit 134. The functional blocks may be software blocks or hardware blocks. For example, the above-mentioned functional blocks may be a single software module realized by software (including a microprogram), or may be a single circuit block on a semiconductor chip (die). Of course, the functional blocks may be a single processor or a single integrated circuit. The method of configuring the functional blocks is arbitrary. The control unit 134 may be configured in functional units different from the above-mentioned functional blocks.

The wireless resource allocation setting unit 1341, for example, performs wireless resource allocation in response to a request from the information processing device 150. The wireless resource allocation setting unit 1341 may be, for example, a function called a scheduler.

1.4. Example of terminal device configuration
Next, a description will be given of the configuration of the terminal device 110. Fig. 4 is a diagram illustrating an example of the configuration of the terminal device 110 according to an embodiment of the present disclosure.

The terminal device 110 includes a communication unit 111, a memory unit 112, an inertial measurement device 114, a control unit 115, and a display unit 116. Note that the configuration shown in FIG. 4 is a functional configuration, and the hardware configuration may be different from this. In addition, the functions of the terminal device 110 may be implemented in a distributed manner across multiple physically separated configurations.

The communication unit 111 is a signal processing unit for wireless communication with other wireless communication devices (e.g., the base station device 130 and other terminal devices 110). The communication unit 111 operates according to the control of the control unit 115. The communication unit 111 may be a wireless transceiver compatible with one or more wireless access methods. For example, the communication unit 41 is compatible with both NR and LTE. The communication unit 111 may be compatible with W-CDMA and cdma2000 in addition to NR and LTE. The communication unit 111 may also be compatible with communication using NOMA.

The communication unit 111 includes a reception processing unit 1111, a transmission processing unit 1112, a network communication unit 113, and an antenna 1114. The communication unit 111 may include a plurality of reception processing units 1111, transmission processing units 1112, and antennas 1114. The configurations of the communication unit 111, reception processing units 1111, transmission processing units 1112, and antennas 1114 are similar to the communication unit 131, reception processing units 1311, transmission processing units 1312, and antennas 1314 of the base station device 130.

The memory unit 112 is a storage device capable of reading and writing data, such as a DRAM, an SRAM, a flash memory, or a hard disk. The memory unit 112 functions as a storage means of the terminal device 110.

The network communication unit 113 is a communication interface for communicating with other devices connected via a network. For example, the network communication unit 113 is a LAN interface such as a NIC. The network communication unit 113 may be a wired interface or a wireless interface. The network communication unit 113 functions as a network communication means of the terminal device 110. The network communication unit 113 communicates with other devices in accordance with the control of the control unit 115. The other devices are, for example, a controller into which the user inputs information related to operations.

The inertial measurement unit 114 is called an IMU (Inertial Measurement Unit) and is a device that detects three-axis angular velocity and acceleration. The inertial measurement unit 114 includes, for example, an acceleration sensor and a gyro sensor. To improve reliability, the inertial measurement unit 114 may be equipped with a magnetic field sensor, an air pressure sensor, a temperature sensor, etc.

The acceleration information and angular velocity information detected by the inertial measurement device 114 is transmitted to the information processing device 150 as information related to inertia (inertial measurement information, an example of information about the user).

Alternatively, the control unit 115 may calculate the user's state (e.g., the direction of the head or gaze, etc.) based on the acceleration information and angular velocity information detected by the inertial measurement unit 114, and transmit the user's state to the information processing device 150. The user's state is, for example, information collectively referred to as pose information.

The control unit 115 is a controller that controls each part of the terminal device 110. The control unit 115 is realized by a processor such as a CPU, MPU, or GPU. For example, the control unit 115 is realized by the processor executing various programs stored in a storage device inside the terminal device 110 using a RAM or the like as a working area. The control unit 115 may be realized by an integrated circuit such as an ASIC or FPGA. The CPU, MPU, GPU, ASIC, and FPGA can all be considered as controllers.

The control unit 115 includes a video application control unit 1151, a display area identification unit 1152, and a rendering unit 1153. Each block constituting the control unit 115 (video application control unit 1151 to rendering unit 1153) is a functional block indicating the function of the control unit 115. These functional blocks may be software blocks or hardware blocks. For example, each of the above-mentioned functional blocks may be a software module realized by software (including a microprogram), or may be a circuit block on a semiconductor chip (die). Of course, each functional block may be a processor or an integrated circuit. The method of configuring the functional blocks is arbitrary. The control unit 45 may be configured in functional units different from the above-mentioned functional blocks.

The video application control unit 1151 is a control unit that controls a video application that performs operations such as playing video content. The video application control unit 1151 launches a video application in response to, for example, an instruction from a user.

The display area determination unit 1152 estimates the user's viewpoint using information about inertia and determines the display area to be displayed on the display unit 116 from the acquired video data.

Based on the video data acquired from the information processing device 150, the rendering unit 1153 generates images to be displayed in each frame in accordance with the display area identified by the display area identification unit 1152, and edits the video.

The display unit 116 is a display device such as a display, and displays various information such as images generated by the rendering unit 1153. The display unit 116 is, for example, a non-transparent, video see-through, or optical see-through display. The display unit 116 plays back the video edited by the rendering unit 1153 by displaying images at a predetermined frame rate.

1.5. Example of network architecture configuration
Here, the architecture of a fifth generation mobile communication system (5G) will be described as an example of a communication system applied to the content distribution system 100 according to an embodiment of the present disclosure. FIG. 5 is a diagram showing an example of the 5G architecture. The 5G architecture includes a UE (User Equipment) 10, a RAN (Radio Access Network)/AN (Access Network) 230, a NGC (Next Generation Core)/5GC (5G Core) 20, and a DN (Data Network) 240.

The 5GC/NGC 20 is also called a 5G core network. The 5GC/NGC 20 is connected to the UE 10 via the RAN/AN 230.

RAN230 is a base station device that provides a wireless interface, and AN230 is, for example, an access point or a router that provides a wired interface. RAN/AN230 includes a base station device called a gNB or ng-eNB.

The 5GC/NGC 20 is composed of a control plane function group 21 and a UPF (User Plane Function) 220.

The control plane function group 21 includes an AUSF (Authentication Server Function) 201, a NEF (Network Exposure Function) 202, a NRF (Network Repository Function) 203, a NSSF (Network Slice Selection Function) 204, a PCF (Policy Control Function) 205, a SMF (Session Management Function) 206, a UDM (Unified Data Management) 207, an AF (Application Function) 208, and an AMF (Access Management Function) 209.

UDM207 has the functions of generating 3GPP AKA authentication information and processing user IDs. UDM207 includes a UDR (Unified Data Repository) that holds and manages subscriber information, and a FE (Front End) section that processes subscriber information.

In addition, AMF209 has functions such as registration processing, connection management, and mobility management for UE10.

SMF206 has functions such as session management, IP allocation and management of UE10. AUSF201 has an authentication function. NSSF204 has a function related to network slice selection. NEF202 has a function of providing network function capabilities and events to third parties, AF208, and edge computing functions.

NRF203 has the function of discovering network functions and maintaining network function profiles. PCF205 has the function of policy control. AF208 has the function of interacting with the core network to provide services.

UPF (User Plane Function) 220 has a function of user plane processing. DN 240 is, for example, an entity that provides a connection to an operator's own service such as an MNO (Mobile Network Operator), an entity that provides an Internet connection, or an entity that provides a connection to a third-party service.

Here, Namf is a service-based interface provided by AMF 209, and Nsmf is a service-based interface provided by SMF 206. Furthermore, Nnef is a service-based interface provided by NEF 202, and Npcf is a service-based interface provided by PCF 205. Nudm is a service-based interface provided by UDM 207, and Naf is a service-based interface provided by AF 208. Nnrf is a service-based interface provided by NRF 203, and Nnssf is a service-based interface provided by NSSF 204. Nausf is a service-based interface provided by AUSF 201. Each of these NFs (Network Functions) exchanges information with other NFs via each service-based interface.

In addition, N1 is a reference point between UE10 and AMF209, and N2 is a reference point between RAN/AN230 and AMF209. N4 is a reference point between SMF206 and UPF220, and information is exchanged between these NFs (Network Functions).

An example of a UE 10 is the terminal device 110 of this embodiment. An example of a RAN/AN 230 is the base station device 130 of this embodiment.

Furthermore, the information processing device 150 may be an edge server installed within 5GC/NGC20 (or installed in the vicinity of 5GC/NGC20), or a cloud server (not shown), or may be a cloud server installed on the Internet.

Alternatively, the information processing device 150 may be composed of multiple devices including, for example, a 5GC. In this case, the inertial measurement information acquisition unit 1531 may be implemented in the AF 208, and the radio resource allocation request unit 1533 may be implemented as a function of the AMF 209 or the SMF 206. The video data generation unit 1532 corresponds to an edge server installed in the 5GC/NGC 20, or a cloud server (not shown), or a cloud server (not shown) installed in the Internet. The video data generation unit 1532 may also be implemented in the AF 208.

<<2. Example of information processing in content distribution system>>
Next, an example of information processing executed by the content distribution system 100 will be described.
<2.1. Content distribution processing example>
FIG. 6 is a sequence diagram illustrating an example of a content distribution process according to an embodiment of the present disclosure.

First, the terminal device 110 launches a video app, for example, in response to a user instruction (step S101), and requests the information processing device 150 to deliver video content specified by the video app via the base station device 130 (step S102).

The terminal device 110 measures information related to inertia (step S103) and transmits the measured information related to inertia to the information processing device 150 via the base station device 130 (step S104). Note that the processing of steps S103 and S104 is performed at a fixed or variable period, or in response to an event.

Based on the acquired inertia information, the information processing device 150 determines the area of the video to be transmitted to the terminal device 110 (step S105), and generates video data of the determined area (step S106).

The information processing device 150 transmits the generated video data to the terminal device 110 via the base station device 130 (step S107).

The terminal device 110 determines a display area for the acquired video data based on the latest measured inertia information (step S108). The terminal device 110 generates images to be displayed in each frame from the acquired video data according to the determined display area, edits the video, and then displays the video on the display unit 116 (step S109).

2.2. Rendering process example
Next, an example of a rendering process executed by the terminal device 110 will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining an example of the rendering process according to an embodiment of the present disclosure. The rendering process described here is executed, for example, in step S109 of Fig. 6.

Figure 7 shows the display timing of an image (hereinafter also referred to as a frame image) generated by the terminal device 110, in other words, the timing of displaying the frame image.

The terminal device 110 displays moving images on the display unit 116 by updating (generating) frame images, which are still images, at a period corresponding to the frame rate.

For example, if the frame rate is K [fps], K frame images #n (n is an integer greater than or equal to 1 and less than or equal to (K+1)) are generated per second and displayed on the display unit 116. In this case, the update period of the frame images is 1/K seconds.

Next, another example of the rendering process executed by the terminal device 110 will be described with reference to FIG. 8. FIG. 8 is a diagram for explaining another example of the rendering process according to an embodiment of the present disclosure. The rendering process described here is executed, for example, in step S109 of FIG. 6.

When rendering a frame image, a technique called time warp may be used to draw the frame image. Time warp is a technique for generating an image of a predicted display area based on acquired video data and the latest inertia information in order to keep the motion-to-photon latency within a certain value. As one application example of this time warp, the rendering unit 1153 sets the frame rate displayed on the display unit 116 to m times (m>1) the frame rate of the video data acquired from the information processing device 150.

In addition, the rendering unit 1153 may apply time warping to the drawing of each frame image in order to keep the motion-to-photon latency within a certain value in a delay environment caused by wireless communication between the information processing device 150 and the terminal device 110.

Here, in VR, it is known that a phenomenon called VR sickness occurs due to a "gap" between the screen seen in front of the user on a head-mounted display (HMD) and the user's physical senses. For example, when a user turns around and the scenery on the screen changes, the scenery actually displayed on the HMD in front of the user may be displayed with a slight delay from the scenery the user thinks it should be. Such a delay is called motion-to-photon latency. Alternatively, when a user moves while recognizing the depth (space), the scenery actually displayed on the HMD in front of the user may be shifted from the scenery the user thinks he or she will see after the movement. When such a delay or gap occurs, VR sickness is more likely to occur.

A known method of improving this VR sickness is to increase the frame rate of the frame images displayed on the display. By increasing the frame rate, the difference between the scenery that the user imagines and the scenery that is actually displayed on the display is reduced, making it possible to suppress the occurrence of VR sickness.

Furthermore, by applying the above-mentioned time warp, VR sickness can be improved by reducing motion-to-photon latency.

In the rendering process described using Figure 7, the frame rate is K [fps], and frame images are updated every 1/K seconds. More specifically, the terminal device 110 generates frame images #1, #2, ... from video data acquired from the information processing device 150 every 1/K seconds. At this time, the terminal device 110 generates frame images #1, #2, ... using the video data acquired each time.

Therefore, if the terminal device 110 attempts to increase the frame rate, for example to suppress the occurrence of VR sickness, it will be necessary to shorten the period for acquiring video data, which will increase the load on wireless communication.

Therefore, the terminal device 110 uses time warp technology to increase the frame rate of the frame images displayed on the display unit 116 without changing the period for acquiring video data from the information processing device 150.

As shown in FIG. 8, the terminal device 110 generates a frame image #1 using the acquired video data D1 and displays it on the display unit 116. The terminal device 110 also generates a frame image #1-1 using the acquired video data D1 and displays it on the display unit 116. At this time, the terminal device 110 uses the latest inertia-related information to perform a time warp process on the video data D1 to generate frame image #1-1. The terminal device 110 uses the latest inertia-related information to determine the user's viewpoint or a field of view including the viewpoint, and determines a display area based on the determined line of sight. This display area is also called a viewport. The terminal device 110 extracts the determined display area from the video data D1 to generate frame image #1-1. In this case, the inertia-related information can be measured, for example, at a period shorter than the display period of the frame image displayed on the display unit 116.

In this way, the terminal device 110 can increase the frame rate without shortening the acquisition period of the video data by generating multiple frame images from one video data using the latest inertia-related information measured at different times. For example, in FIG. 8, the terminal device 110 generates two frame images #1 and #1-1 from one video data D1. This allows the terminal device 110 to shorten the period (hereinafter also referred to as the frame period) for display on the display unit 116 to 1/2 compared to the case where one frame image #1 is generated from one video data D1.

The terminal device 110 can reduce motion-to-photon latency and suppress VR sickness by reflecting changes in inertia-related information in the same video data and shortening the frame period. This method of reflecting changes in inertia-related information in the same video data is called the above-mentioned time warp or asynchronous time warp (ATW). By applying this time warp or asynchronous time warp, it is possible to reduce motion-to-photon latency and shorten the frame period.

<2.3. Communication processing example>
Next, an example of a communication process executed in the content distribution system 100 will be described with reference to Figures 9 to 11. As described above with reference to Figure 5, the content distribution system 100 employs the NR network architecture.

Here, in the NR network architecture, for example, registration with the 5GC/NGC20 is performed so that the UE10 can receive services via the 5GC/NGC20. The UE10 selects, for example, a PLMN (Public Land Mobile Network) corresponding to the 5GC/NGC20, and executes a registration procedure.

Below, an example of communication processing, including the registration processing, performed by UE10 to receive services via 5GC/NGC20 is described using Figures 9 to 11.

(Registration process)
First, a registration process performed by the UE 10 will be described with reference to Fig. 9. Fig. 9 is a sequence diagram showing an example of the registration process according to the embodiment of the present disclosure.

As shown in Figure 9, UE 10 in the RM-DEREGISTERED state, i.e., not registered with 5GC/NGC 20, transmits a Registration Request message to RAN/AN 230 to perform initial registration (step S301). At this time, UE 10 transmits the registration request message including the UE identity.

If the UE has a valid EPS GUTI, the UE identity is the 5G-GUTI mapped from the EPS GUTI. Here, EPS (Evolved Packet System) refers to the 4G system equivalent to LTE (Long Term Evolution) and is composed of EUTRAN and EPC. From a security standpoint, the EPS GUTI (Globally Unique Temporary Identifier) is a temporary ID used to identify the UE within the EPS, instead of an ID uniquely assigned to each UE, such as an IMSI (International Mobile Subscriber Identity) or IMEI (International Mobile Equipment Identity).

Alternatively, the UE identity is a PLMN-specific 5G-GUTI assigned by the PLMN to which UE10 is attempting to register, if available.

Alternatively, the UE identity is a PLMN-specific 5G-GUTI assigned by the PLMM, which is treated as the equivalent PLMN for the PLMN (Public Land Mobile Network) to which the UE 10 is attempting to register, if available.

Alternatively, the UE identity is a PLMN-specific 5G-GUTI assigned by any PLMN, if available.

Otherwise, the UE 10 includes a Subscription Concealed Identifier (SUCI) in the registration request message. Here, the SUCI is an encrypted version of a Subscription Permanent Identifier (SUPI), which is an ID uniquely assigned to each UE 10.

UE10 includes in the registration request message a mapping of each S-NSSAI (Single NSSAI) of the Requested NSSAI with the S-NSSAIs of the HPLMN (Home PLMN). This allows confirmation of whether the S-NSSAI(s) of the Requested NSSAI (Network Slice Selection Assistance Information) can be permitted based on the Subscribed S-NSSAIs.

In addition, if UE10 is using the Default Configured NSSAI, it includes the Default Configured NSSAI Indication in the registration request message.

Here, the S-NSSAI consists of a mandatory SST (Slice/Service Type) that identifies the slice type, and an optional SD (Slice Differentiator) that distinguishes different slices within the same SST. Note that the mandatory SST is 8 bits, and the optional SD is 24 bits.

Note that all or each of the services for AR, VR, MR (Mixed Reality), SR (Substitutional Reality), and XR (X Reality or extended reality) applications may be defined as a slice identified by this S-NSSAI. In other words, services for AR, VR, MR, SR, and XR applications may be realized by one or more network slices. That is, services for AR, VR, MR, SR, and XR applications may be associated with one or more S-NSSAIs.

Here, AR, also known as augmented reality, is a technology that extends the virtual world, such as 3D images and characters created with CG (Computer Graphics), by overlaying it onto the real world.

VR, also known as virtual reality, is a technology that allows you to experience a virtual world using 360-degree images captured with CG and 360-degree cameras.

MR, also known as mixed reality, is a technology that closely blends the real world with the virtual world to make the virtual world appear more realistic.

SR, also known as alternate reality, is a technology that allows you to perceive a virtual world as replacing the real world.

XR is a general term for technologies that create experiences that add some kind of change to the real world, including AR, VR, MR, and SR.

When RAN/AN230 receives a registration request message from UE10, it performs AMF Selection (step S302). If the registration request message does not include 5G-S-TMSI (5G S-Temporary Mobile Subscription Identifier) or GUAMI (Globally Unique AMF Identifier), RAN/AN230 selects AMF209 based on (R)AT (Radio Access Technology) and, if available, Requested NSSAI. Alternatively, if the registration request message does not include 5G-S-TMSI or GUAMI indicating a valid AMF209, RAN/AN230 selects AMF209 based on (R)AT (Radio Access Technology) and, if available, Requested NSSAI.

If RAN/AN230 is an NG-RAN, a registration request including the selected PLMN ID or a combination of PLMN ID and NID (Network Identifier) that identifies the SNPN (Standalone Nonpublic Network) is forwarded to AMF209 (step S303).

If UE10 has not provided SUCI to AMF209, AMF209 initiates an Identity Request process and sends an Identity Request message to UE10 to request SUCI (step S304).

When UE10 receives the Identity Request message in step S304, it responds with an Identity Response message including the SUCI (step S305). Here, UE10 can obtain the SUCI using the public key of the HPLMN.

AMF209 performs AUSF Selection based on SUPI or SUCI (step S306) and initiates authentication of UE10.

When AUSF201 receives an authentication request from AMF209, it must perform authentication of UE10.

AUSF201 selects UDM207 for authentication processing and obtains authentication data from UDM207.

When UE10 is authenticated, AUSF201 provides security-related information to AMF209.

If authentication is successful at AMF209, AMF209 initiates NGAP (NG Application Protocol) processing and provides security context to RAN/AN230.

RAN/AN230 retains the security context and returns a response to AMF209.

RAN/AN230 then uses this security context to protect messages exchanged with UE10.

AMF209 performs UDM Selection based on the SUPI and selects UDM207 (step S307).

AMF209 is registered to UDM207 using Nudm_UECM_Registration (step S308).

If AMF209 does not have subscriber information (Subscription Data) for UE10, it uses Nudm_SDM_Get (step S309) to obtain Subscription Data such as Access and Mobility Subscription data and SMF Selection Subscription data (step S310).

After obtaining the Access and Mobility Subscription data from the UDM 207, the AMF 209 generates a UE context. The Access and Mobility Subscription data includes information indicating whether the NSSAI may be included in plain text in the RRC Connection Establishment in 3GPP Access.

AMF209 sends a registration accept to UE10 (step S311). The registration accept message includes 5G-GUTI and Registration Area. The N2 message including the registration accept message includes Allowed NSSAI.

Allowed NSSAIs include only S-NSSAIs that do not require Network Slice-Specific Authentication and Authorization based on subscriber information, or S-NSSAIs that have successfully completed Network Slice-Specific Authentication and Authorization based on the UE context of AMF209.

In addition, AMF209 may provide a list of equivalent PLMNs to UE10 registered in a PLMN, but AMF209 must not provide a list of equivalent PLMNs to UE10 registered in a SNPN.

UE10 sends a Registration Complete message to AMF209 to notify that a new 5G-GUTI has been assigned (step S312).

Following the above registration process, UE10 becomes registered with 5GC/NGC20, i.e., becomes in RM-REGISTERED state.

(PDU session establishment process)
Next, a PDU session establishment process performed by the UE 10 will be described with reference to Fig. 10. Fig. 10 is a sequence diagram showing an example of a PDU session establishment process according to an embodiment of the present disclosure.

As shown in Fig. 10, UE 10 registered in AMF 209 transmits a PDU Session Establishment Request message to AMF 209 (step S401). Here, the PDU Session Establishment Request message includes an S-NSSAI corresponding to the requested service among the Allowed NSSAIs, and a UE Requested DNN (Data Network Name). The UE Requested DNN is a DNN that enables connection to services such as AR, VR, MR, SR, and XR.

Upon receiving the PDU session establishment request message, AMF209 performs SMF Selection (step S402). Here, if the PDU session establishment request message includes an S-NSSAI but does not include a DNN, the default DNN for this S-NSSAI is selected as the DNN. For example, assume that all or each of the services for the AR, VR, MR, SR, and XR applications are defined as slices identified by a specific S-NSSAI. In this case, the default DNN for the specific S-NSSAI is a DNN that enables connection to the AR, VR, MR, SR, and XR services.

The AMF 209 sends an Nsmf_PDUSession_CreateSMContext Request including the S-NSSAI of the Allowed NSSAI to the selected SMF 206 (step S403). Here, the Nsmf_PDUSession_CreateSMContext Request includes a SUPI, an S-NSSAI, a UE Requested DNN, or a DNN.

If the Session Management Subscription data corresponding to the SUPI, DNN and S-NSSAI is not available, the SMF 206 uses Nudm_SDM_Get to obtain the Session Management Subscription data from the UDM 207. The SMF 206 also uses Nudm_SDM_Subscribe to register to be notified when the Session Management Subscription data is updated.

Upon receiving the Nsmf_PDUSession_CreateSMContext Request, SMF206 generates an SM context if it can process the PDU session establishment request. Then, SMF206 responds with an Nsmf_PDUSession_CreateSMContext Response to AMF209 and provides the SM Context ID (step S404).

If a second authentication and authorization process needs to be performed by the DN-AAA server during the establishment of the PDU session, SMF206 initiates a PDU Session establishment authentication/authorization process (step S405).

If dynamic Policy and Charging Control (PCC) is applied to the PDU session to be established, SMF206 performs PCF Selection (step S406). Otherwise, SMF206 may apply local policies.

In addition, the SMF 206 may execute the SM Policy Association Establishment procedure to establish an SM Policy Association with the PCF 205 and obtain default PCC Rules for the PDU session (step S407). This allows the PCC Rules to be obtained before selecting the UPF 220.

SMF206 performs UPF Selection to select one or more UPFs 220 (step S408).

SMF206 sends an N4 Session Establishment Request message to the selected UPF220 (step S409).

The UPF 220 responds to the SMF 206 by returning an N4 Session Establishment Response message (step S410).

If multiple UPFs 220 are selected for a PDU session, this N4 session establishment process is initiated for each UPF 220.

The SMF 206 sends a Namf_Communication_N1N2MessageTransfer message to the AMF 209 (step S411). Here, the Namf_Communication_N1N2MessageTransfer message includes a PDU Session ID, N2 SM information, CN Tunnel Info, S-NSSAI of the Allowed NSSAI, and an N1 SM container. Here, the N2 SM information includes a PDU Session ID, QFI(s), QoS Profile(s), etc. Also, when multiple UPFs 220 are used for a PDU session, the CN Tunnel Info includes tunneling information related to these multiple UPFs 220 that terminate N3.

The N1 SM container includes a PDU Session Establishment Accept that the AMF 209 must provide to the UE 10. The PDU Session Establishment Accept also includes the S-NSSAI of the Allowed NSSAI.

The Namf_Communication_N1N2MessageTransfer message includes a PDU Session ID so that AMF209 knows which access to use for UE10.

The AMF 209 transmits an N2 PDU Session Request message to the RAN/AN 230 (step S412). Here, the AMF 209 transmits a NAS (Non-Access-Stratum) message including a PDU Session ID and a PDU Session Establishment Accept with the UE 10 as the destination, and the N2 SM information received from the SMF 206 to the RAN/AN 230 via the N2 PDU Session Request message.

RAN/AN 230 forwards a NAS message including the PDU Session ID and the N1 SM container to UE 10 (step S413). Here, the N1 SM container includes a PDU Session Establishment Accept.

RAN/AN230 responds with an N2 PDU Session Response message to AMF209 (step S414).

AMF209 forwards the N2 SM information received from RAN/AN230 to SMF206 via an Nsmf_PDUSession_UpdateSMContext Request message including the SM Context ID and the N2 SM information (step S415).

The SMF 206 initiates an N4 Session Modification procedure with the UPF 220 and sends an N4 Session Modification Request message to the UPF 220 (step S416). The SMF 206 provides the UPF 220 with AN tunneling information (AN Tunnel Info) in addition to the forwarding rules.

The UPF 220 responds with an N4 Session Modification Response message to the SMF 206 (step S417). If multiple UPFs 220 are used in the PDU session, the above N4 session modification procedure is performed on all UPFs 220 that terminate N3.

The PDU session is established according to the above process.

For each QoS flow, the QoS Profile must include QoS parameters, such as 5QI (5G QoS Identifier) and ARP (Allocation and Retention Priority).

A QoS flow may be either "GBR (Guaranteed Bit Rate)" or "Non-GBR" depending on the QoS Profile.

For Non-GBR QoS flows, the QoS Profile may include a QoS parameter called RQA (Reflective QoS Attribute).

For GBR QoS flows, the QoS parameters must include uplink and downlink Guaranteed Flow Bit Rate (GFBR) and Maximum Flow Bit Rate (MFBR).

5QIs are parameters for access nodes to control the forwarding process of QoS flows, such as scheduling weights, admission thresholds, queue management thresholds, link layer settings, etc.

The ARP contains information on priority level, pre-emption capability, and pre-emption vulnerability.

The ARP priority level defines the relative importance of a QoS flow and is set in the range of 1 to 15, with 1 being the highest importance.

ARP pre-emption capability is a metric that defines whether a QoS flow can use resources that are already allocated to another QoS flow with a lower priority level.

ARP pre-emption vulnerability is a metric that defines whether or not a QoS flow will give up resources allocated to it in order to allow other QoS flows with a higher priority level.

ARP pre-emption capability and ARP pre-emption vulnerability must be set to either "enabled" or "disabled".

(RRC_CONNECTED transition processing)
Signaling between the UE 10 and the core network (e.g., the AMF 209) is performed by NAS signaling. A NAS signaling connection is used to enable this NAS signaling.

The NAS signaling connection is composed of an AN signaling connection between UE10 and an Access Network (AN) and an N2 connection between the AN and AMF209. Here, the AN signaling connection is, for example, a Radio Resource Control (RRC) connection.

Therefore, using Figure 11, we will explain the RRC_CONNECTED transition process that transitions the RRC state of UE 10 from RRC_IDLE to RRC_CONNECTED. Figure 11 is a sequence diagram showing an example of the RRC_CONNECTED transition process according to an embodiment of the present disclosure. The RRC_CONNECTED transition process is initiated by UE 10 (an example of terminal device 110) when transitioning from RRC_IDLE to RRC_CONNECTED.

First, it is assumed that UE 10 is in RRC_IDLE and CM-IDLE states (step S500). Here, the RRC_IDLE state is a state in which an RRC connection is not established with the base station device 130. The CM-IDLE state is a state in which a NAS signaling connection via N1 is not established with the AMF 209.

UE 10 sends an RRC Setup Request message via SRB (Signalling Radio Bearer) 0 to establish a new connection with base station device 130 (step S501).

When UE 10 receives an RRC setup (RRCSetup) message from base station device 130 (step S502), it transitions the RRC state from RRC_IDLE to RRC_CONNECTED, while maintaining CM-IDLE (step S503).

When the base station device 130 receives an RRC setup complete (RRCSetupComplete) message from UE 10 (step S504), it completes the RRC setup process and UE 10 transitions to CM-CONNECTED (step S505).

The initial NAS message (INITIAL UE MESSAGE) from UE 10, sent together with the RRC setup complete (RRCSetupComplete) message, is sent to AMF 209 (step S506).

Here, the first NAS message is, for example, a Registration Request message (see step S301 in FIG. 9) or a PDU Session Establishment Request message (step S401 in FIG. 10). In addition, several NAS messages are exchanged between UE 10 and AMF 209.

The AMF 209 prepares UE context data and transmits the UE context data to the base station device 130 via an INITIAL CONTEXT SETUP REQUEST message (step S507). Here, the UE context data includes PDU session context, Security Key, UE Radio Capability, UE Security Capabilities, etc.

The base station device 130 sends a SecurityModeCommand message to the UE 10 (step S508), and when the UE 10 sends a SecurityModeComplete message to the base station device 130 via SRB1 (step S509), the base station device 130 activates AS (Access-Stratum) security.

To set up SRB2 and DRBs (Data Radio Bearers), base station device 130 sends an RRCReconfiguration message to UE 10 (step S510), and when UE 10 sends an RRCReconfigurationComplete message to base station device 130 via SRB1 (step S511), the RRC reconfiguration process is completed.

The base station device 130 sends an initial context setup completion (INITIAL CONTEXT SETUP RESPONSE) message to the AMF 209 (step S512) to notify that the setup process is complete.

(SPS-Config and ConfiguredGrantConfig settings)
When the AMF 209 receives a PDU session establishment request message (see step S401 in FIG. 10) including an S-NSSAI (e.g., S-NSSAI1) corresponding to a specific service from the terminal device 110, the AMF 209 selects an SMF 206 for providing a service corresponding to this S-NSSAI1. Here, the specific service is, for example, a service for an application of AR, VR, MR, SR, or XR.

In addition, the SMF 206 selected to provide services corresponding to S-NSSAI1 selects the PCF 205 and UPF 220 required to provide services for applications, such as AR, VR, MR, SR, and XR.

Furthermore, for example, the base station device 130 may determine the SPS-Config and ConfiguredGrantConfig to be set for the downlink and uplink with the terminal device 110, respectively, in response to an instruction from AMF 209.

The base station device 130 can set the SPS-Config and ConfiguredGrantConfig in the terminal device 110 via RRC. For example, the base station device 130 sets the SPS-Config and ConfiguredGrantConfig in the terminal device 110 by including them in an RRC reconfiguration message (see step S508 in FIG. 11) and transmitting the message.

SPS-Config is used to configure downlink Semi-Persistent Transmission. Multiple SPSs (Semi-Persistent Scheduling) can be configured for one BWP (Bandwidth Part) of a serving cell. Multiple SPSs are configured in the SPS-ConfigList.

In addition to the method called Type 1 via RRC described above, the base station device 130 can also set the ConfiguredGrantConfig using a method called Type 2 via a PDCCH that specifies a CS-RNTI (Radio Network Temporary Identifier).

The SPS-Config information element included in the RRC message includes the fields periodicity, periodicityExt, and SPS-ConfigIndex.

Here, if the SPS-Config information element does not include periodicityExt, the periodicity is referenced; if periodicityExt is included, the periodicity is ignored.

TS38.331 defines the following values for the periodicity of SPS-Config: 10 ms, 20 ms, 32 ms, 40 ms, 64 ms, 80 ms, 128 ms, 160 ms, 320 ms, and 640 ms.

In addition, with regard to periodicityExt in SPS-Config, when SCS (Subcarrier Spacing) is 15 kHz, it is defined that any number of slots between 1 slot and 640 slots can be set as periodicityExt. When SCS is 30 kHz, it is defined that any number of slots between 1 slot and 1280 slots can be set as periodicityExt. When SCS is 60 kHz, it is defined that any number of slots between 1 slot and 2560 slots can be set as periodicityExt. When SCS is 120 kHz, it is defined that any number of slots between 1 slot and 5120 slots can be set as periodicityExt.

When SPS is configured, the MAC entity must determine that the Nth downlink allocation occurs in a slot (Slot#_N) within a System Frame Number (SFN) that satisfies the following equation (1):

(numberOfSlotsPerFrame×SFN+Slot#_N)=
[(numberOfSlotsPerFrame×SFNinit+slotinit)
+N x periodicity x numberOfSlotsPerFrame/10]
modulo(1024×numberOfSlotsPerFrame)...(1)

Here, numberOfSlotsPerFrame is the number of slots in a radio frame (for example, 10 if the SCS is 15 kHz), and SFNinit and slotinit are the SFN and slot# at which the SPS was configured and the first PDSCH (Physical Downlink Shared Channel) transmission was performed.

In addition, a parameter numberOfSlotsPerSPS may be introduced to allocate multiple consecutive slots on the time axis as SPS resources. The MAC entity determines that the Nth downlink allocation will occur in numberOfSlotsPerSps consecutive slots starting from the slot (Slot#_N) in the SFN that satisfies the above formula (1).

The ConfiguredGrantConfig information element includes the fields periodicity, periodicityExt, and ConfiguredGrantConfigIndex.

Here, if the ConfiguredGrantConfig information element does not contain periodicityExt, the periodicity is referenced; if periodicityExt is included, the periodicity is ignored.

In TS38.331, the periodicity of ConfiguredGrantConfig is defined as 2, 7, or n*14 symbols when the SCS is 15 kHz, where n is one of the following values: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320, or 640.

Furthermore, with regard to periodicityExt in ConfiguredGrantConfig, for example, when the SCS is 15 kHz, it is defined that any number of symbols between 1 symbol and 640 symbols can be set as periodicityExt, and a period of periodicityExt*14 symbols can be set.

When a CG (Configured Grant) is set, the MAC entity must determine that the Nth uplink allocation occurs at a symbol (Symbol#_N) in Slot# of a SFN (System Frame Number) that satisfies the following equation (2):

[(SFN×numberOfSlotsPerFrame×numberOfSymbolsPerSlot)
+(Slot#×numberOfSymbolsPerSlot)+Symbol#_N]=
(timeDomainOffset×numberOfSymbolsPerSlot+S+N×periodicity)
modulo(1024×numberOfSlotsPerFrame×numberOfSymbolsPerSlot)...(2)

Here, numberOfSlotsPerFrame is the number of slots in a radio frame (for example, 10 if the SCS is 15 kHz), and numberOfSymbolsPerSlot is the number of symbols in a slot (14 for Normal CP). In addition, timeDomainOffset and S are parameters obtained from SLIV (Start and length indicator value). timeDomainOffset is the offset value on the time axis of the resources at SFN=0, and S is the symbol (Symbol#) to which the PUSCH (Physical Uplink Shared Channel) was first assigned.

In addition, a parameter numberOfSymbolsPerCg may be introduced to allocate multiple consecutive symbols on the time axis as CG resources. The MAC entity determines that the Nth uplink allocation occurs for numberOfSymbolsPerCg consecutive symbols starting from the symbol (Symbol#_N) in Slot# in SFN that satisfies the above formula (2).

<<3. Technical issues >>
Next, technical issues of the content delivery system 100 according to the embodiment of the present disclosure will be described, particularly focusing on the case where video data is transmitted by semi-persistent transmission.

Figure 12 is a diagram for explaining an example of video data distribution by a content distribution system. In Figure 12, video data is communicated between a base station device 130 and a terminal device 110 via SPS. The terminal device 110 also uses the above-mentioned time warp to double the frame rate and display the video.

For example, in order to use the XR service, the terminal device 110, which is an HMD, sends a PDU session establishment request message including S-NSSAI1 (see step S401 in FIG. 10) to the AMF 209. The AMF 209 that receives the PDU session establishment request message instructs the base station device 130 to set SPS-Config and ConfiguredGrantConfig on the downlink and uplink with the terminal device 110, respectively.

The terminal device 110 receives video data at a frame rate of, for example, 45 fps by downlink SPS (Semi-Persistent Scheduling) via the base station device 130. Hereinafter, the frame rate of the video data transmitted by the information processing device 150 is also referred to as the first frame rate.

In addition, the terminal device 110 transmits information related to inertia measured by the inertial measurement device 114 via the base station device 130 using an uplink CG (Configured Grant).

The terminal device 110 utilizes time warping on the received video data of the first frame rate (45 fps) to display the video as a video with a frame rate of, for example, 90 fps. Hereinafter, the frame rate of the video that the terminal device 110 displays on the display unit 116 is also referred to as the second frame rate.

Video at the second frame rate (90 fps) is displayed on the display of the terminal device 110 at a cycle of 11.11 ms. Also, it is ideal to receive video data at the first frame rate (45 fps) at a cycle of 22.22 ms. However, since the SPS cycle is set in slot units (1 ms when the SCS is 15 kHz), it is set to the closest cycle, for example, 22 ms.

Here, we will explain how to set the SPS period. Information related to the format, including the frame rate, of the video handled by the service corresponding to S-NSSAI1 is stored, for example, in a UDR (Unified Data Repository).

When establishment of a PDU session is requested to provide a service corresponding to S-NSSAI1, SMF206 obtains information regarding the format, including the frame rate, of the video handled by the service corresponding to S-NSSAI1 from the UDR and provides it to AMF209 via a NAS message.

AMF209 determines the SPS period from the acquired information related to the video format and instructs the base station device 130 to set the SPS with the determined period.

In addition, SMF206 may determine the SPS period based on information related to the format, including the frame rate of the video handled by the service corresponding to S-NSSAI1 obtained from the UDR, and provide the SPS period to the base station device 130 via AMF209. For example, this SPS period may be included in the QoS Profile or QoS parameters included in the N2 SM information that SMF206 provides to the base station device 130 via AMF209.

Furthermore, the QoS Profile or QoS parameters may include information to explicitly indicate the setting of SPS. For example, "sps-enabled" may be set.

In addition, SMF206 may include the SPS period and information for explicitly instructing the SPS settings, such as "sps-enabled", in the Alternative QoS Profile provided to the base station device 130.

Alternatively, information regarding the format, including the frame rate, of the video handled by the service corresponding to S-NSSAI1 may be included in the PCC Rules provided from PCF205 to SMF206.

In addition, a QFI (QoS Flow Identifier) and a 5QI (5G QoS Identifier) corresponding to the video format handled by the service corresponding to S-NSSAI1 or the SPS period may be defined, and the SMF 206 may notify the base station device 130 of this QFI and 5QI.

At the NAS level, a QoS flow is characterized by the QoS Profile provided by the 5GC to the base station device 130 and the QoS rule(s) provided by the 5GC to the terminal device 110. The QoS Profile is used by the base station device 130 to determine how to process the flow in the radio interface.

The QoS Profile includes QoS parameters, for example 5QI and ARP.

QoS rule(s) are used to indicate the correspondence between uplink user plane data and QoS flows. For example, CG configuration is included in the QoS rule.

Here, the CG settings are the CG period, and further, information to explicitly indicate the CG settings, such as "cg-enabled".

At the AS level, the DRB determines how packets are handled on the radio interface. The mapping of QoS flows to DRBs by the base station device 130 is based on the QoS Profile associated with the QFI.

As described above, the terminal device 110 receives video data at a cycle of 22 ms and displays video (frame images) on the display unit 116 at a cycle of 11.11 ms.

In the example shown in FIG. 12, the terminal device 110 receives video data D1 over a predetermined reception period from point A. The terminal device 110 displays a first video generated from the received video data D1 at the next display timing (point B1). The terminal device 110 also displays a second video generated from the video data D1 at point B2 as a time warp of the first video displayed at point B1 (hereinafter also referred to as time warp display).

The terminal device 110 receives video data at a cycle of 22 ms and displays the video at a display cycle of 11.11 ms. More specifically, the terminal device 110 displays a first video at a cycle of 22.22 ms and time-warps a second video at a cycle of 22.22 ms.

In this way, the cycle in which the terminal device 110 receives video data (the SPS cycle) is different from the cycle in which the terminal device 110 displays the first video (the first frame rate). Therefore, even if the timing of receiving video data and the timing of displaying video at the first frame rate (45 fps) are aligned at a certain point in time, as at point A in Figure 12, a gradual gap will arise between the reception timing and the display timing. Although this gap is slight, as the gap gradually accumulates, the amount of delay until display becomes too large to be ignored from the perspective of motion-to-photon latency, or conversely, problems will arise in which the display is not in time.

Outline of Proposed Technology Therefore, this disclosure proposes a technology that allows a terminal device 110 that periodically receives video data and periodically displays video to stably display video. As the proposed technology, a base station device 130 changes a setting related to the reception timing when a difference between the periodic reception timing of the video data in the terminal device 110 and the display timing of the video satisfies a predetermined condition.

＜＜4. Technical Features＞＞
<4.1. Resetting SPS>
FIG. 13 is a diagram for explaining SPS reconfiguration by a base station device 130 according to an embodiment of the present disclosure.

As described above, the terminal device 110 receives video data at a period of 22 ms, and the terminal device 110 displays the first video at a period of 22.22 ms.

In this way, if the period in which the terminal device 110 receives video data (the SPS period) is different from the period in which the terminal device 110 displays the first video, a discrepancy (difference) occurs between the reception timing and the display timing.

When the absolute value of the difference between the reception timing at which the terminal device 110 receives the video data and the display timing of the first video becomes equal to or greater than a predetermined threshold, the base station device 130 resets the current SPS setting and sets the SPS again. The base station device 130 resets the SPS-Config so that the reception timing at which the terminal device 110 receives the video data and the display timing of the first video are aligned.

When the absolute value of the difference between the reception timing of receiving video data and the display timing of the first video becomes equal to or greater than a predetermined threshold value, the terminal device 110 receives the video data at the changed reception timing based on the reconfigured SPS-Config.

Figure 14 is a flowchart showing the flow of the SPS reconfiguration process according to an embodiment of the present disclosure. Figure 14 shows the case where the SPS reconfiguration process is performed by the terminal device 110.

The terminal device 110 sets the SPS based on a notification from the base station device 130 (e.g., an RRC message including SPS-Config) (step S601). The terminal device 110 receives video data from the base station device 130 at the set SPS period (step S602).

The terminal device 110 measures the accumulated time of the difference between the SPS period (e.g., 22 ms) and the frame rate of the video data (e.g., the first frame rate, 22.22 ms) (step S603). More specifically, the terminal device 110 accumulates the difference (0.22 ms) between the SPS period and the first frame rate each time it receives video data, and calculates the difference from the display timing at the reception timing of the video data.

In addition, the terminal device 110 may calculate the difference between the reception timing and the display timing by calculating the difference between the time when the video data is received and the time when the video data is displayed.

The terminal device 110 determines whether the measured cumulative time is equal to or greater than a predetermined threshold value (step S604). If the cumulative time is less than the threshold value (step S604; No), the process returns to step S602, and the terminal device 110 receives video data at the SPS period.

On the other hand, if the accumulated time is greater than or equal to the threshold (step S604; Yes), the terminal device 110 initiates a process to request the base station device 130 to reconfigure the SPS (step S605) and returns to step S601.

In step S605, the terminal device 110 may report the cumulative time to be corrected or the number of slots equivalent to this cumulative time to be corrected as an offset value in the request for SPS reconfiguration (reconfiguration of SPS-Config).

When the base station device 130 receives a request to reconfigure the SPS-Config from the terminal device 110, the base station device 130 reconfigures the SPS based on the reported information related to the cumulative time to be corrected. The request to reconfigure the SPS-Config is made via an RRC message.

The terminal device 110 executes the above-mentioned SPS reconfiguration process while receiving video data.

Note that, here, the terminal device 110 requests SPS reconfiguration, but this is not limited to this (i.e., the request for SPS reconfiguration by the terminal device 110 may not be a required component). For example, the base station device 130 may calculate the difference between the display timing at the reception timing of the video data and the display timing to determine whether to reconfigure the SPS. In this case, the base station device 130 may obtain information regarding the frame rate of the video data from, for example, the information processing device 150. In addition or instead, the base station device 130 may obtain information regarding the frame rate of the video data from the NF of UDR or 5GC/NGC20. In addition or instead, the base station device 130 may obtain information on the upper layer that is not originally terminated (i.e., information regarding the frame rate of the video data) by reading it using DPI (Deep Packet Inspection) or the like.

Alternatively, the base station device 130 may be made to reconfigure the SPS based on the difference between the display timing and the reception timing at which the NF of 5GC/NGC20 receives the video data. Here, a case will be described in which the SMF206 instructs the base station device 130 on the timing to reconfigure the SPS.

In this case, in addition to S-NSSAI1, the terminal device 110 includes in the PDU session establishment request message (see step S401 in Figure 10) that it sends to receive the service corresponding to S-NSSAI1 the absolute value of the cumulative time difference between the SPS period and the video frame rate period that the terminal device 110 can tolerate.

SMF206 obtains S-NSSAI1 and the cumulative time acceptable to terminal device 110 from AMF209 via Nsmf_PDUSession_CreateSMContext Request (see step S401 in Figure 10).

Here, the terminal device 110 notifies the allowable cumulative time, but this is not limited to the above. For example, the SMF 206 may set a predetermined value based on the motion-to-photon latency, etc., as the allowable cumulative time.

SMF206 obtains information regarding the format, including the frame rate, of the video handled by the service corresponding to S-NSSAI1 from the UDR.

The SMF 206 determines the period of the SPS based on the frame rate of the video, and determines the period for setting the SPS based on the allowable cumulative time. Here, the period for setting the SPS is the period from when the SPS is set until when the SPS needs to be reset.

AMF209 obtains the SPS period and the period for setting the SPS from SMF206 via N2 SM information of Namf_Communication_N1N2MessageTransfer (see step S411 in Figure 10).

AMF209 notifies base station device 130 of the SPS period and period for setting SPS acquired from SMF206, and the number of slots corresponding to the cumulative time to be corrected as an offset value, via an N2 PDU session request message (see step S412 in FIG. 10).

The base station device 130 sets an SPS period for the downlink with the terminal device 110 based on the SPS period and the period for setting the SPS obtained from the AMF 209, and starts a timer that sets the period for setting the SPS.

When this timer expires, the base station device 130 reconfigures the SPS by offsetting the slot at which the SPS starts by the number of slots equivalent to the offset value, and resets the timer.

From then on, this SPS reconfiguration process is repeated until terminal device 110 terminates the service corresponding to S-NSSAI1.

<4.2. Multiple SPS Settings>
In the above example, the base station device 130 sets one SPS, but the base station device 130 may set multiple SPSs. This allows the base station device 130 to increase resources allocated to the SPSs.

Figures 15 and 16 are diagrams for explaining an example of SPS setting by a base station device 130 relating to an embodiment of the present disclosure.

As shown in FIG. 15, the base station device 130 may set multiple SPSs in multiple consecutive slots within an SPS period (e.g., 22 ms). Alternatively, the base station device 130 may set multiple SPSs in multiple distributed slots as shown in FIG.

The base station device 130 assigns video data to multiple slots, for example, where SPS is set, and transmits the data.

In addition, the base station device 130 may reconfigure the SPS by switching between each SPS of multiple SPSs.

In addition, in Figures 15 and 16, the base station device 130 sets the SPS in multiple slots from the beginning of the SPS cycle, but this is not limited to this. The base station device 130 may set the SPS in multiple slots from the end of the SPS cycle, or may set the SPS in multiple slots located in the center of the SPS cycle. Also, in Figures 15 and 16, the number of resource allocations for which the base station device 130 sets the SPS is three, but this is not limited to this and may be two or four or more.

In addition, the base station device 130 sets the terminal device 110 to discontinuous reception (DRX) in order to periodically monitor the PDCCH. One of the processes performed by the terminal device 110 in idle mode is to monitor the PDCCH that notifies paging from the base station device 130. Therefore, in the idle mode, DRX is set to periodically monitor the PDCCH in order to reduce power consumption during standby.

It is also important to reduce power consumption in the terminal device 110 in connected mode. Therefore, the base station device 130 can set C-DRX (Connected mode DRX) using RRC Connection Setup or RRC ConnectionReconfiguration. The value of longDRX-Cycle is set according to the monitoring period of the PDCCH, and the values of drxStartOffset and onDurationTimer are set based on the slot position to which the PDCCH is assigned. Furthermore, the base station device 130 receives scheduling information via the PDCCH and sets drx-InactivityTimer as the period for receiving data indicated by the scheduling information. Furthermore, in addition to this Long DRX, the base station device 130 can set Short DRX.

Short DRX is set by drxShortCycleTimer and shortDRX-Cycle. The terminal device 110 in connected mode monitors the PDCCH according to the Long DRX setting. If demodulation of the PDCCH including scheduling information is successful for the period during which onDurationTimer is valid, the drx-InactivityTimer is started, and data indicated by the scheduling information can be received for the period during which drx-InactivityTimer is valid. When the drx-InactivityTimer expires, the terminal device 110 starts the drxShortCycleTimer and monitors the PDCCH at a period of shortDRX-Cycle, which is more frequent than the longDRX-Cycle, for the period during which the drxShortCycleTimer is valid. By monitoring the PDCCH at this shortDRX-Cycle, for example, it is possible to ensure the QoS of packets transmitted in a short period. When the drxShortCycleTimer expires, the terminal device 110 resumes periodic monitoring of the PDCCH according to the Long DRX setting.

The base station device 130 sets the C-DRX in the terminal device 110 based on the PDCCH monitoring period and the SPS period. For example, when the PDCCH is notified within a slot in which the SPS is set, one Long DRX is set. The value of longDRX-Cycle is set according to the SPS period, and the values of drxStartOffset and onDurationTimer are set based on the slot position in which the SPS is set. Here, when SPS is set in multiple consecutive slots (FIG. 15), the value of onDurationTimer is set according to the number of consecutive slots. Alternatively, the values of drxStartOffset and onDurationTimer of Long DRX are set according to the first slot position in which the SPS is set, and the value of drx-InactivityTimer is set according to the position of the second or subsequent slots. When SPS is set to multiple distributed slots (FIG. 16), the value of onDurationTimer is set so that all of the multiple distributed slots are included. Alternatively, when SPS is set to multiple distributed slots, the values of drxStartOffset and onDurationTimer of Long DRX are set according to the position of the first slot in which SPS is set, and drxShortCycleTimer and shortDRX-Cycle of Short DRX are set according to the position of the second or subsequent slots. The value of drxShortCycleTimer is set based on the period of the slots set in a distributed manner within the SPS period, and shortDRX-Cycle is set based on the period including the multiple slots set in a distributed manner.

In addition, when the PDCCH is notified in a slot adjacent to the slot in which SPS is set, a longDRX-Cycle value is set according to the SPS period, and the drxStartOffset and onDurationTimer values are set based on the positions of the adjacent slot and the slot in which SPS is set. In other words, the PDCCH is monitored and data sent using the slot in which SPS is set is received over the period of onDurationTimer.

Note that this single Long DRX setting is reset when the SPS is reset. When the SPS is reset by switching between multiple SPSs, the Long DRX is reset each time the SPS is switched. The values of drxStartOffset, onDurationTimer, or drx-InactivityTimer are reset based on the slot position of the switched SPS. In order to update each DRX parameter during this DRX reset, each parameter may be notified via DCI.

In addition, the monitoring period of the PDCCH and the period of the SPS may be set flexibly, that is, two independent Long DRXs may be set to set different periods. A first Long DRX is set for monitoring the PDCCH, and a second Long DRX is set for receiving data via the SPS. The value of the first longDRX-Cycle is set according to the monitoring period of the PDCCH, and the values of the first drxStartOffset and the first onDurationTimer are set according to the slot for notifying the PDCCH. The value of the second longDRX-Cycle is set according to the SPS period, and the values of the second drxStartOffset and the second onDurationTimer are set based on the slot position in which the SPS is set. In addition, the method shown in the case of setting one Long DRX described above can be used for setting the second Long DRX. Here, when the period of the first onDurationTimer and the period of the second onDurationTimer overlap part or all of them, the terminal device 110 judges the period which is the logical sum (OR) of the periods of the first onDurationTimer and the second onDurationTimer as the period of the onDurationTimer. Also, when the period between the timing of the end of the first onDurationTimer and the timing of the start of the second onDurationTimer, or the period between the timing of the end of the second onDurationTimer and the start of the first onDurationTimer, is equal to or less than a certain threshold, it is considered that it becomes difficult to control the on/off of the reception system of the terminal device 110. In such a case, the terminal device 110 can avoid the problem of controlling the on and off of the receiving system by setting a continuous period including the periods of the first onDurationTimer and the second onDurationTimer as the period of the third onDurationTimer. In addition, the threshold value for this determination (e.g., 5 slots, etc.) may be notified to the terminal device 110 as one of the parameters of Long DRX (e.g., DurationThreshold) when setting the second Long DRX. Note that the above-mentioned concept of slots in the setting of SPS or DRX may include minislots.

Figure 17 is a diagram illustrating an example of SPS configuration by a base station device 130 relating to an embodiment of the present disclosure.

In FIG. 17, the base station device 130 sets multiple SPSs having the same period within the SPS period (e.g., 22 ms).

The base station device 130 sets resource allocations 701 to 704 corresponding to, for example, four SPSs with any slot intervals in the downlink with the terminal device 110. In FIG. 17, there is a gap of six slots between resource allocations 701 and 702, between resource allocations 702 and 703, and between resource allocations 703 and 704. There is also a gap of four slots between resource allocation 704 and resource allocation 701 of the next period.

The base station device 130 may individually activate each of the configured multiple resource allocations using DCI (Downlink Control Information). Here, for example, the base station device 130 first activates only the SPS corresponding to resource allocation 701.

Assume that the cumulative time difference between the period of the SPS and the period of the first frame rate of the video is equal to or greater than the time difference between resource allocation 701 and resource allocation 702, that is, 6 slots in the example of Figure 17. In this case, the base station device 130 deactivates the SPS corresponding to resource allocation 701 using DCI and activates the SPS corresponding to resource allocation 702.

Next, assume that the cumulative time difference between the period of the SPS and the period of the first frame rate of the video becomes equal to or greater than 6 slots, which is the time difference between resource allocation 702 and resource allocation 703. In this case, the base station device 130 deactivates the SPS corresponding to resource allocation 702 using DCI, and activates the SPS corresponding to resource allocation 703.

Next, assume that the cumulative time difference between the period of the SPS and the period of the first frame rate of the video becomes equal to or greater than 6 slots, which is the time difference between resource allocation 703 and resource allocation 704. In this case, base station device 130 deactivates the SPS corresponding to resource allocation 703 using DCI, and base station device 130 activates the SPS corresponding to resource allocation 704.

Similarly, assume that the cumulative time difference between the SPS period and the period of the first frame rate of the video becomes equal to or greater than four slots, which is the time difference between resource allocation 704 and resource allocation 701 of the next period. In this case, the base station device 130 deactivates the SPS corresponding to resource allocation 704 using DCI, and activates the SPS corresponding to resource allocation 701.

From then on, the activation/deactivation process for each SPS of the multiple SPSs set will continue until the terminal device 110 terminates the service corresponding to S-NSSAI1.

As described above, when the base station device 130 switches the SPS used to transmit video data, it may notify the terminal device 110 of the SPS offset before and after the switch, for example using DCI.

Here, information regarding the SPS period, the number of SPSs to be set within the SPS period, the arrangement of resource allocations corresponding to each SPS within the SPS period, and the period from activation to deactivation of each SPS is notified from SMF 206 to base station device 130 during the PDU session establishment process.

<4.3. Resetting CG>
In applications such as AR, VR, MR, SR, and XR, where free viewpoint video and real-time video are viewed on an HMD, it is important to suppress the motion-to-photon latency within a certain value as described above. Therefore, in order to reflect head movement, viewpoint, or changes in the field of view including the viewpoint in each frame image of the video, a periodic uplink occurs in which the terminal device 110 transmits information related to the latest inertia detected. Therefore, when the terminal device 110 sends a PDU session establishment request to the AMF 209 to receive a service corresponding to S-NSSAI1, the 5GC sets a CG (Configured Grant) in addition to the above-mentioned SPS. Here, the CG setting method can be the same as the SPS setting method described so far.

Also, in the PDU session establishment process for the service corresponding to S-NSSAI1, the selected SMF206 may use AF208 to provide the service corresponding to S-NSSAI1.

AF208 determines the SPS settings, for example, when an application used by terminal device 110 requires periodic downlink reception. Furthermore, when the application involves receiving video, AF208 identifies the video format and determines the required SPS settings according to the identified video format.

AF208 may also determine the CG settings when the application used by terminal device 110 requires periodic uplink transmission. For example, in order to reflect the information related to inertia detected by terminal device 110 in the video received by the application, the CG settings are determined taking into account the frame rate of the video. In other words, AF208 provides other NFs or base station device 130 with information to assist with the settings required to receive video data and the settings required to transmit information used to generate video data (e.g., information related to inertia), based on the format of the video handled by the application.

The SPS settings and CG settings determined by AF208 are provided to the base station device 130 via SMF206 and AMF209.

In the above example, the base station device 130 reconfigures the SPS, but the base station device 130 may also reconfigure the ConfiguredGrantConfig (CGConfig). This point will be described with reference to Figures 18 and 19.

Figures 18 and 19 are diagrams for explaining CG reconfiguration by a base station device 130 relating to an embodiment of the present disclosure.

As shown in FIG. 18, during the inertial measurement information reception period, the information processing device 150 periodically receives the inertial measurement information via the base station device 130. The period at this time is determined by the period of the uplink communication in which the base station device 130 receives the inertial measurement information from the terminal device 110, and is, for example, identical to the CG period set in ConfiguredGrantConfig.

Based on the received inertial measurement information, the information processing device 150 executes a video data generation process to generate video data, and transmits the video data to the terminal device 110 via the base station device 130. Such video data is transmitted at an SPS period by data transmission using SPS.

When the SPS period and the CG period are the same, the information processing device 150 can generate video data based on the most recently received inertial measurement information.

In this case, when the cumulative time difference between the SPS period and the first frame rate becomes equal to or greater than a threshold, the base station device 130 performs SPS reconfiguration. This causes a delay in data transmission using the SPS.

In the example of Figure 18, the SPS is reconfigured so that the transmission timing of data transmission using the SPS is advanced. Therefore, even if the information processing device 150 generates video data based on the most recently received inertial measurement information, the video data cannot be transmitted because it will not be able to be transmitted in time for the reconfigured transmission timing. Alternatively, in order to transmit the video data, the information processing device 150 will have to generate the video data using inertial measurement information received most recently or previously.

Therefore, as shown in FIG. 19, the base station device 130 according to this embodiment reconfigures the ConfiguredGrant (CG) when reconfiguring the SPS. At this time, it is desirable for the base station device 130 to reconfigure the CG prior to the timing of reconfiguring the SPS. This allows the information processing device 150 to generate video data based on the latest inertial measurement information most recently received, even if the SPS is reconfigured.

<4.4. Time Warp Changes>
In the above example, the base station device 130 reconfigures the SPS or CG to reduce the difference between the communication timing and the display timing that occurs in the terminal device 110, but the method for reducing the difference is not limited to this. For example, the terminal device 110 may reduce the difference by adjusting the number of time warp images that are displayed using time warp.

Figure 20 is a diagram illustrating an example of display processing by a terminal device 110 relating to an embodiment of the present disclosure.

As shown in FIG. 20, the terminal device 110 generates and displays a frame image (hereinafter also referred to as a first image) using the latest inertial information from the video data received during the reception period of the SPS cycle. The terminal device 110 also performs time warp display of a frame image (time warp image) generated in a similar manner. The terminal device 110 displays the first image or the time warp image as a frame image at a second frame rate.

In this case, due to the accumulation of slight discrepancies between the SPS period and the first frame rate (45 fps), a state occurs in which the reception of video data does not keep up with the display timing of the first image. In Figure 20, at point B, a state occurs in which the reception of video data does not keep up with the display timing of the first image.

Let us say that the cumulative time difference between the SPS period and the first frame rate period exceeds a certain threshold, and the display timing of the first image cannot be made in time. As shown in the lower diagram of Fig. 20, at the timing when the first image would normally be displayed, the terminal device 110 displays a time warped image in which time warping has been applied to the video data received at the previous reception timing. This allows the terminal device 110 to delay the display timing of the first image by half a period, and to display the first image generated using the most recently received video data.

In the above example, we explained the case where the timing of receiving the video data is delayed and the first image is not displayed in time, but we will now explain the case where the timing of receiving the video data is early.

Figure 21 is a diagram illustrating another example of display processing by a terminal device 110 relating to an embodiment of the present disclosure.

The accumulation of slight discrepancies between the SPS period and the first frame rate (45 fps) period can result in a situation in which the delay between receiving video data and the timing at which the first image generated based on the video data is displayed becomes large. In Figure 21, at point D, the delay between receiving video data and the timing at which the first image is displayed becomes so large that, for example, motion-to-photon latency cannot be ignored.

In this way, the cumulative time difference between the SPS period and the first frame rate period exceeds a certain threshold, and the delay between receiving video data and the display timing of the first image becomes so large that the motion-to-photon latency cannot be ignored.

As shown in the lower diagram of Fig. 21, the terminal device 110 displays a first image generated from the most recently received video data at the timing (point C) when it displays a time warped image obtained by applying time warp to the video data received at the previous reception timing. This enables the terminal device 110 to advance the display timing of the first image by half a cycle, thereby reducing the effects of motion-to-photon latency.

4.5. Setting Priority
In the above-mentioned examples, the case where one video data is assigned to one SPS has been described, but the present invention is not limited to this. For example, the base station device 130 may assign video data divided into multiple regions to multiple SPSs according to the priority of each region. Here, each divided video data is, for example, data called a segment.

Figures 22 to 25 are figures for explaining an example of a video data allocation process by a base station device 130 relating to an embodiment of the present disclosure.

The information processing device 150 sets the user's viewpoint or a field of view including the viewpoint based on the latest inertia information acquired from the terminal device 110. Furthermore, the information processing device 150 determines an area so that the set viewpoint or field of view point is at the center, and generates video data of the determined area.

At this time, as shown in Fig. 22, the information processing device 150 divides the generated video data into multiple regions. Then, the information processing device 150 changes the resolution of the divided regions according to the distance between the set user's viewpoint and the divided regions.

For example, as shown in FIG. 22, the information processing device 150 generates video data assuming that the user's viewpoint is located at the center of the video data, and divides the generated video data into nine 3 x 3 regions.

In this case, as shown in FIG. 23, the information processing device 150 sets the resolution of the divided regions, region 801, which is closest to the viewpoint and located in the center, to the highest (high resolution). The information processing device 150 also sets the resolution of the divided regions, regions 806-809, which are farthest from the viewpoint and located at the corners of the video data, to the lowest (low resolution). The information processing device 150 sets the resolution of the remaining regions 802-805 to a resolution between high resolution and low resolution (medium resolution). Regions 802-805 are regions that border region 801, which is closest to the viewpoint, on their sides, and regions 806-809 are regions that border regions 802-805 on their sides.

Note that, although the case where video data is divided into nine parts has been described here, the number of divisions of image data is not limited to nine. The number of divisions may be between two and eight, or may be ten or more. Also, although the case where the resolution of the regions is divided into three, low, medium, and high, has been described here, the number of resolutions is not limited to three. The number of resolutions may be two, or may be four or more. Furthermore, although the case where each divided region is the same size has been described here, the example is not limited to each region being the same size. For example, it may be divided into regions of different sizes.

Here, multiple formats with different resolutions may be predefined as video data that can be applied to each region. In other words, the information processing device 150 generates video data by selecting a video format with a different resolution depending on the distance from the viewpoint.

The information processing device 150 may select a video format with a different resolution based on the communication quality between the terminal device 110 and the base station device 130 in addition to the distance from the viewpoint. For example, the AF 208 includes a wireless communication quality acquisition unit (not shown) and acquires the communication quality between the terminal device 110 and the base station device 130 from the base station device 130. The wireless communication quality acquisition unit provides the communication quality between the terminal device 110 and the base station device 130 acquired from the base station device 130 to the information processing device 150.

As shown in Figure 24, AF208 assigns priorities according to the resolution of each region of the video. High priority is assigned to high resolution region 801, medium priority is assigned to medium resolution regions 802-805, and low priority is assigned to low resolution regions 806-809. Here, the priorities are, for example, QFI (QoS Flow identifier) and 5QI (5G QoS Identifier).

Here, the QoS flow is the concept of the finest granularity for differentiating QoS within a PDU session, and in 5GS, the QoS flow is identified by the QFI. At N3 between the UPF 220 and the RAN/AN 230 corresponding to the base station device 130, each data flow is sent with the encapsulated QFI added to the header. Note that the QFI may be equivalent to the 5QI.

AMF209 determines the SPS settings, including the SPS period, based on the frame rate of the video in each priority area. Here, AMF209 may set the frame rate of the video in each priority area to the same, or may lower the frame rate of the video in a low priority area.

In addition, the SPS settings for each priority are determined taking into consideration that videos in areas with higher priority are received by the terminal device 110 earlier in time than videos in areas with lower priority.

The SPS settings for each priority determined by AMF209 are provided to the base station device 130 via SMF206 and AMF209.

The base station device 130 performs SPS resource allocation based on the SPS settings for each priority obtained from the AMF 209.

In the example shown in FIG. 25, the base station device 130 sets a periodic SPS resource allocation 810 for high priority, a periodic SPS resource allocation 811 for medium priority, and a periodic SPS resource allocation 812 for low priority.

The base station device 130 identifies the priority based on the QFI added to the data flow received from the UPF 220, and transmits the data of each area of the video data using resource allocation according to the priority. For example, the base station device 130 transmits the high priority area 801 to the terminal device 110 using resource allocation 810. Similarly, the base station device 130 transmits the medium priority areas 802-805 to the terminal device 110 using resource allocation 811, and transmits the low priority areas 806-809 to the terminal device 110 using resource allocation 812.

Furthermore, information including the mapping and the format of each region required for the rendering unit 1153 of the terminal device 110 to restore the divided videos to one video is transmitted using periodic resource allocation 810 for sending high priority data. Here, the information including the mapping and the format of each region required for restoring the divided videos to one video may be, for example, an MPD (Media Presentation Description) or a file for a similar purpose.

Based on this mapping and information including the format of each region, the rendering unit 1153 can apply a decoding method appropriate to the format of each divided region to restore it as video data of a single region.

The rendering unit 1153 sets the timing of the video frame to be displayed (e.g., see point B1 in FIG. 12) based on the timing set by the SPS that first received data via periodic resource allocation 810 (e.g., see point A in FIG. 12). The timing of this video frame is subject to an offset period that takes into account, for example, the period required for decoding, the period required for rendering processing, and a margin. This offset period is controlled by the video application control unit 1151.

Here, an example is shown in which the resolution of the divided regions is changed according to the distance between the user's viewpoint and the divided regions, but only the priority may be changed without changing the resolution of each divided region. The information processing device 150 sets the priority of the divided regions, which are closest to the viewpoint and located in the center, 801, to the highest (high priority). The information processing device 150 also sets the priority of the divided regions, which are farthest from the viewpoint and located in the corners of the video data, 806 to 809, to the lowest (low priority). The information processing device 150 sets the priority of the remaining regions 802 to 805 to a priority between high and low priority (medium priority). Here, the priority is, for example, QFI and 5QI.

In addition, when transmitting data for each region, the order of transmission may be determined based on pixels. For example, the information processing device 150 prioritizes transmission of pixel information for a specific portion of the frame image so that a low-resolution image can be displayed even if the terminal device 110 is unable to receive information for all pixels within a specified period of time. Next, control is performed so that pixel information for the remaining portion is transmitted. The base station device 130 transmits data for each region to the terminal device 110 according to the priority based on these pixels. The rendering unit 1153 synthesizes the multiple low-resolution frame images received to generate a high-resolution frame image.

<<5. Other embodiments>>
The above-described embodiment is merely an example, and various modifications and applications are possible.

In the above embodiment, an example is shown in which a video with a frame rate of 45 fps is displayed at 90 fps using time warp, but the frame rate is not limited to this example. The technology disclosed herein may be applied to the display of videos with various frame rates.

In the above embodiment, the information processing device 150 generates video data based on information related to inertia and transmits it to the terminal device 110. That is, the information processing device 150 generates video data corresponding to the user's viewpoint from 360-degree video information and transmits it to the terminal device 110, for example, but is not limited to this. For example, the information processing device 150 may transmit the 360-degree video data as is to the terminal device 110. In this case, the information processing device 150 may reduce the amount of transmitted data by transmitting, for example, 360-degree video data with low resolution. In addition, the information processing device 150 may transmit both the video data corresponding to the user's viewpoint and the 360-degree video data with reduced resolution to the terminal device 110.

In the above embodiment, the NF of the base station device 130 or 5GC/NGC20 acquires the frame rate, but this is not limited to the above. In other words, the information on the frame rate acquired by the NF of the base station device 130 or 5GC/NGC20 may be not only the value of the frame rate itself (e.g., 45 fps or 90 fps) but also an index corresponding to the frame rate (e.g., QFI or 5QI).

Although an example has been shown in which the information for restoring divided videos to one video includes mapping and the format of each region, the information for restoring this divided video to one video may also include information about the frame rate. The NF of the base station device 130 or 5GC/NGC20 may obtain the frame rate via the information for restoring this divided video to one video.

In addition, in the above-described embodiment, a case has been described in which the terminal device 110 receives video data on the downlink and transmits information related to inertia on the uplink, but this is not limited to the above. For example, the data received by the terminal device 110 may be data that is received periodically in real time, and may be other than video data. Furthermore, the data transmitted by the terminal device 110 may be data that is transmitted periodically in real time, and may be other than information related to inertia. In this way, the technology disclosed herein may be applied to various types of data communication that is performed periodically in real time.

<<6. Application Examples>>
In addition, in some embodiments, the settings of the SPS or CG described above may take into account the requirements of services (e.g., cloud gaming) using augmented reality (AR)/virtual reality (VR)/mixed reality (MR)/substitutional reality (SR).

Several services are being considered as use cases for 5G NR (New Radio). Of these, AR/VR services are expected to be the killer content of 5G NR. 3GPP TR 22.842 v17.1.0 and TS 22.261 v17.0.1 specify requirements for rendering game images for cloud gaming using AR/VR. More specifically, these technical specifications and reports describe motion-to-photon delay and motion-to-sound delay as the allowable delay in rendering game images that does not cause AR/VR users to feel uncomfortable with the movement of the images, as follows:

Motion-to-photon latency: While maintaining the required data rate (1Gbps), the motion-to-photon latency is in the range of 7-15ms.
Motion-to-sound latency: less than 20ms.

Note that motion-to-photon delay is defined as the delay between the physical movement of the user's head and the updated image in the AR/VR headset (e.g., Head Mount Display). Also, motion-to-sound delay is defined as the delay between the physical movement of the user's head and the updated sound waves from the head mounted speaker reaching the user's ear. The AR/VR headset and head mounted speaker here may be the terminal device 110 in this disclosure.

To meet these latency requirements, the above-mentioned technical specifications and reports stipulate that the 5G system must meet the following two rendering requirements:

Max Allowed End-to-end latency: 5 ms (i.e., the total allowable latency of the uplink and downlink between a terminal (e.g., the terminal device 110) and an interface to a data network (e.g., a network in which an Application Function (AF) is located) is 5 ms),
Service bit rate: user-experienced data rate: 0.1Gbps (100Mbps) (i.e., throughput capable of supporting AR/VR content).

Rendering here includes cloud rendering, edge rendering, and split rendering. Cloud rendering is where AR/VR data is rendered on the network cloud (on a certain entity based on the core network (including UPF) arrangement and data network (including application server and AF) arrangement that do not take into account the user's location). Edge rendering is where AR/VR data is rendered on the network edge (on a certain entity (e.g., an Edge Computing Server (an application server in a data network in a network arrangement for Edge Computing)) based on the core network (including UPF) arrangement and data network (including application server and AF) arrangement close to the user's location). Split rendering means that part of the rendering is performed on the cloud and the other part is performed on the edge.

Figure 26 is an image diagram of a rendering server and an AR/VR client related to rendering. Figure 26 is described in the technical report mentioned above. Here, the AR/VR client may correspond to the terminal device 110 in the present disclosure. Also, the Cloud Render Server may correspond to the information processing device 150 in the present disclosure. Also, the Cloud Render Server may be an application server (e.g., an Edge Computing Server) for edge computing in a Local Area Data Network (LADN) to which the Local UPF connected to the base station device 130 in the present disclosure serves as an interface. Also, the Cloud Render Server may be named an Edge Render Server or a Split Render Server.

In this application example, for example, in the case of data communication (e.g., session (PDU session), bearer (Radio Bearer), packet flow (QoS flow)) requiring motion-to-photon delay (7-15 ms) or motion-to-sound delay (less than 20 ms), the above-mentioned SPS or CG reconfiguration may be performed.

In another aspect, the above-mentioned SPS or CG reconfiguration may be performed in the case of data communication (e.g., session (PDU session), bearer (Radio Bearer), packet flow (QoS flow)) where the rendering requirement Max Allowed End-to-end latency (5 ms) is required.

<<7. Conclusion>>
Although the preferred embodiment of the present disclosure has been described in detail above with reference to the attached drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person having ordinary knowledge in the technical field of the present disclosure can conceive of various modified or amended examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure.

Of the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically by known methods. In addition, the information including the processing procedures, specific names, various data and parameters shown in the above documents and drawings can be changed as desired unless otherwise specified. For example, the various information shown in each figure is not limited to the information shown in the figures.

In addition, each component of each device shown in the figure is a functional concept, and does not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

In addition, the above-described embodiments can be combined as appropriate to the extent that they do not cause any contradictions in the processing content.

In addition, the effects described in this specification are merely descriptive or exemplary and are not limiting. In other words, the technology disclosed herein may provide other effects that are apparent to a person skilled in the art from the description in this specification, in addition to or in place of the above effects.

Note that the following configurations also fall within the technical scope of the present disclosure.
(1)
a wireless communication unit that transmits video data to a terminal device at a predetermined period;
a control unit that changes a setting related to the reception timing when a difference between a periodic reception timing at which the terminal device receives the video data and a display timing at which the video data is displayed on the terminal device at a predetermined frame rate satisfies a predetermined condition; and
A base station device comprising:
(2)
The base station device according to (1), wherein the setting regarding the reception timing is a Semi-Persistent Scheduling (SPS) setting.
(3)
The base station device according to (1) or (2), wherein the control unit changes the setting related to the reception timing by resetting the reception timing so that the reception timing and the display timing are aligned.
(4)
The base station device according to any one of (1) to (3), wherein the control unit changes the setting regarding the reception timing by notifying the terminal device of an offset indicating the changed reception timing.
(5)
A base station device according to any one of (1) to (4), wherein, when the settings regarding a plurality of the reception timings are set in the terminal device, the control unit changes the settings regarding the reception timings by notifying the terminal device of the settings to be deactivated and the settings to be newly activated among the settings regarding the plurality of the reception timings.
(6)
The base station device according to any one of (1) to (5), wherein the predetermined condition is that the difference is equal to or greater than a threshold, or that the cumulative difference is equal to or greater than a threshold.
(7)
The base station device according to any one of (1) to (6), wherein the control unit changes the setting regarding the reception timing in response to a request from the terminal device.
(8)
The base station device according to any one of (1) to (7), wherein the control unit changes the setting regarding the reception timing in response to an instruction from a network function belonging to a connected network.
(9)
The base station device according to any one of (1) to (8), wherein the control unit acquires information regarding the frame rate from a content server that acquires the video data.
(10)
The base station device according to any one of (1) to (9), wherein the terminal device generates images from the video data based on information regarding a user's viewpoint, and adjusts the number of images generated in accordance with the difference when displaying the video data at a second frame rate greater than the frame rate.
(11)
the control unit transmits each of the plurality of divided areas of the video data at the setting of the reception timing according to a priority of the area;
The priority of the region is set based on information about a user's viewpoint.
A base station device according to any one of (1) to (10).
(12)
the priority of the region is set according to a resolution of the region that is set based on information about the user's viewpoint;
A base station device as described in (11).
(13)
a wireless communication unit that receives video data from a base station device at a predetermined period;
A control unit for displaying the video data at a predetermined frame rate;
Equipped with
when a difference between a periodic reception timing for receiving the video data and a display timing for displaying the video data at the predetermined frame rate satisfies a predetermined condition, the wireless communication unit receives the video data based on the changed setting of the reception timing.
Terminal device.
(14)
Transmitting video data to a terminal device at a predetermined period;
changing a setting related to the reception timing when a difference between a periodic reception timing at which the terminal device receives the video data and a display timing at which the video data is displayed on the terminal device at a predetermined frame rate satisfies a predetermined condition;
A communication method including:
(15)
receiving video data from a base station device at a predetermined period;
displaying the video data at a predetermined frame rate;
when receiving the moving image data, if a difference between a periodic reception timing for receiving the moving image data and a display timing for displaying the moving image data at the predetermined frame rate satisfies a predetermined condition, receiving the moving image data based on the changed setting of the reception timing;
A communication method including:
(16)
a wireless communication unit that receives information about a user from a terminal device at a first period and transmits video data generated based on the information about the user at a second period;
a control unit that changes a setting related to a transmission timing at which the terminal device periodically transmits information about the user when a difference between a periodic reception timing at which the terminal device receives the video data and a display timing at which the video data is displayed on the terminal device at a predetermined frame rate satisfies a predetermined condition;
A base station device comprising:
(17)
The base station device according to (1), wherein the control unit further sets a period of intermittent reception and an on period based on settings related to the reception timing.
(18)
The base station device according to (17), wherein the control unit sets one discontinuous reception as the discontinuous reception setting and assigns a downlink control channel to an on period in the one discontinuous reception setting.
(19)
The control unit sets, as the discontinuous reception setting, a second discontinuous reception setting different from a first discontinuous reception setting for monitoring a downlink control channel;
The base station device according to (17), wherein the cycle and on period of the second intermittent reception are set based on settings related to the reception timing.
(20)
The base station device according to (19), wherein the control unit sets a threshold value related to an interval between a first on-period of the first discontinuous reception and a second on-period of the second discontinuous reception as a setting of the second discontinuous reception.
(21)
The terminal device according to (13), wherein the wireless communication unit sets a period of intermittent reception and an on period based on the setting of the reception timing.
(22)
the wireless communication unit sets, as the discontinuous reception setting, a second discontinuous reception setting different from a first discontinuous reception setting for monitoring a downlink control channel;
Here, the cycle and on period of the second intermittent reception are set based on the setting of the reception timing, in the terminal device described in (21).
(23)
The terminal device according to (22), wherein the wireless communication unit sets a third on period including the first on period and the second on period when a first on period of the first intermittent reception overlaps with part or all of a second on period of the second intermittent reception.
(24)
The terminal device described in (22), wherein the wireless communication unit sets a threshold value related to the interval between the first on period of the first intermittent reception and the second on period of the second intermittent reception as the second intermittent reception setting, and when the interval between the first on period of the first intermittent reception and the second on period of the second intermittent reception is equal to or less than the threshold value, sets a third on period including the first on period and the second on period.

100 Content distribution system 110 Terminal device 130 Base station device 131 Communication unit 134 Control unit 150 Information processing device

Claims (16)

a wireless communication unit that transmits video data to a terminal device at a predetermined period;
a control unit that changes a setting related to the reception timing when a difference between a periodic reception timing at which the terminal device receives the video data and a display timing at which the video data is displayed on the terminal device at a predetermined frame rate satisfies a predetermined condition; and
A base station device comprising: A base station device as described in claim 1, wherein the setting regarding the reception timing is a Semi-Persistent Scheduling (SPS) setting. The base station device of claim 1, wherein the control unit changes the setting regarding the reception timing by resetting the reception timing so that the reception timing and the display timing are aligned. The base station device of claim 1, wherein the control unit changes the setting regarding the reception timing by notifying the terminal device of an offset indicating the changed reception timing. The base station device according to claim 1, wherein the control unit, when the settings related to a plurality of the reception timings are set in the terminal device, changes the settings related to the reception timings by notifying the terminal device of the settings to be deactivated and the settings to be newly activated among the settings related to the plurality of the reception timings. A base station device as described in claim 1, wherein the specified condition is that the difference is greater than or equal to a threshold value, or that the cumulative difference is greater than or equal to a threshold value. The base station device described in claim 1, wherein the control unit changes the settings regarding the reception timing in response to a request from the terminal device. The base station device of claim 1, wherein the control unit changes the settings regarding the reception timing in response to an instruction from a network function belonging to the connected network. The base station device described in claim 1, wherein the control unit acquires information regarding the frame rate from a content server that acquires the video data. The base station device of claim 1, wherein the terminal device generates images from the video data based on information about the user's viewpoint, and adjusts the number of images generated according to the difference when displaying the video data at a second frame rate greater than the frame rate. the control unit transmits each of the plurality of divided areas of the video data at the setting of the reception timing according to a priority of the area;
The priority of the region is set based on information about a user's viewpoint.
The base station device according to claim 1 . the priority of the region is set according to a resolution of the region that is set based on information about the user's viewpoint;
The base station device according to claim 11. a wireless communication unit that receives video data from a base station device at a predetermined period;
A control unit for displaying the video data at a predetermined frame rate;
Equipped with
when a difference between a periodic reception timing for receiving the video data and a display timing for displaying the video data at the predetermined frame rate satisfies a predetermined condition, the wireless communication unit receives the video data based on the changed setting of the reception timing.
Terminal device. Transmitting video data to a terminal device at a predetermined period;
changing a setting related to the reception timing when a difference between a periodic reception timing at which the terminal device receives the video data and a display timing at which the video data is displayed on the terminal device at a predetermined frame rate satisfies a predetermined condition;
A communication method including: receiving video data from a base station device at a predetermined period;
displaying the video data at a predetermined frame rate;
when receiving the moving image data, if a difference between a periodic reception timing for receiving the moving image data and a display timing for displaying the moving image data at the predetermined frame rate satisfies a predetermined condition, receiving the moving image data based on the changed setting of the reception timing;
A communication method including: a wireless communication unit that receives information about a user from a terminal device at a first period and transmits video data generated based on the information about the user at a second period;
a control unit that changes a setting related to a transmission timing at which the terminal device periodically transmits information about the user when a difference between a periodic reception timing at which the terminal device receives the video data and a display timing at which the video data is displayed on the terminal device at a predetermined frame rate satisfies a predetermined condition;
A base station device comprising:

Images